Merge PR #146: feat: 提升流式网关稳定性与安全策略强化

2026-01-04 22:45:01 +08:00
parent 27ed042c56 f8e7255c32
commit 46dda58355
62 changed files with 2575 additions and 551 deletions
--- a/README.md
+++ b/README.md
@@ -268,6 +268,15 @@ default:
  rate_multiplier: 1.0
 ```

+Additional security-related options are available in `config.yaml`:
+
+- `cors.allowed_origins` for CORS allowlist
+- `security.url_allowlist` for upstream/pricing/CRS host allowlists
+- `security.csp` to control Content-Security-Policy headers
+- `billing.circuit_breaker` to fail closed on billing errors
+- `server.trusted_proxies` to enable X-Forwarded-For parsing
+- `turnstile.required` to require Turnstile in release mode
+
 ```bash
 # 6. Run the application
 ./sub2api
--- a/README_CN.md
+++ b/README_CN.md
@@ -268,6 +268,15 @@ default:
  rate_multiplier: 1.0
 ```

+`config.yaml` 还支持以下安全相关配置：
+
+- `cors.allowed_origins` 配置 CORS 白名单
+- `security.url_allowlist` 配置上游/价格数据/CRS 主机白名单
+- `security.csp` 配置 Content-Security-Policy
+- `billing.circuit_breaker` 计费异常时 fail-closed
+- `server.trusted_proxies` 启用可信代理解析 X-Forwarded-For
+- `turnstile.required` 在 release 模式强制启用 Turnstile
+
 ```bash
 # 6. 运行应用
 ./sub2api
--- a/backend/cmd/server/main.go
+++ b/backend/cmd/server/main.go
@@ -86,7 +86,8 @@ func main() {
 func runSetupServer() {
 	r := gin.New()
 	r.Use(middleware.Recovery())
-	r.Use(middleware.CORS())
+	r.Use(middleware.CORS(config.CORSConfig{}))
+	r.Use(middleware.SecurityHeaders(config.CSPConfig{Enabled: true, Policy: config.DefaultCSPPolicy}))

 	// Register setup routes
 	setup.RegisterRoutes(r)
--- a/backend/cmd/server/wire_gen.go
+++ b/backend/cmd/server/wire_gen.go
@@ -76,7 +76,7 @@ func initializeApplication(buildInfo handler.BuildInfo) (*Application, error) {
 	dashboardHandler := admin.NewDashboardHandler(dashboardService)
 	accountRepository := repository.NewAccountRepository(client, db)
 	proxyRepository := repository.NewProxyRepository(client, db)
-	proxyExitInfoProber := repository.NewProxyExitInfoProber()
+	proxyExitInfoProber := repository.NewProxyExitInfoProber(configConfig)
 	adminService := service.NewAdminService(userRepository, groupRepository, accountRepository, proxyRepository, apiKeyRepository, redeemCodeRepository, billingCacheService, proxyExitInfoProber)
 	adminUserHandler := admin.NewUserHandler(adminService)
 	groupHandler := admin.NewGroupHandler(adminService)
@@ -101,10 +101,10 @@ func initializeApplication(buildInfo handler.BuildInfo) (*Application, error) {
 	antigravityTokenProvider := service.NewAntigravityTokenProvider(accountRepository, geminiTokenCache, antigravityOAuthService)
 	httpUpstream := repository.NewHTTPUpstream(configConfig)
 	antigravityGatewayService := service.NewAntigravityGatewayService(accountRepository, gatewayCache, antigravityTokenProvider, rateLimitService, httpUpstream, settingService)
-	accountTestService := service.NewAccountTestService(accountRepository, geminiTokenProvider, antigravityGatewayService, httpUpstream)
+	accountTestService := service.NewAccountTestService(accountRepository, geminiTokenProvider, antigravityGatewayService, httpUpstream, configConfig)
 	concurrencyCache := repository.ProvideConcurrencyCache(redisClient, configConfig)
-	concurrencyService := service.ProvideConcurrencyService(concurrencyCache, accountRepository, configConfig)
-	crsSyncService := service.NewCRSSyncService(accountRepository, proxyRepository, oAuthService, openAIOAuthService, geminiOAuthService)
+	concurrencyService := service.NewConcurrencyService(concurrencyCache)
+	crsSyncService := service.NewCRSSyncService(accountRepository, proxyRepository, oAuthService, openAIOAuthService, geminiOAuthService, configConfig)
 	accountHandler := admin.NewAccountHandler(adminService, oAuthService, openAIOAuthService, geminiOAuthService, rateLimitService, accountUsageService, accountTestService, concurrencyService, crsSyncService)
 	oAuthHandler := admin.NewOAuthHandler(oAuthService)
 	openAIOAuthHandler := admin.NewOpenAIOAuthHandler(openAIOAuthService, adminService)
@@ -125,7 +125,7 @@ func initializeApplication(buildInfo handler.BuildInfo) (*Application, error) {
 	userAttributeService := service.NewUserAttributeService(userAttributeDefinitionRepository, userAttributeValueRepository)
 	userAttributeHandler := admin.NewUserAttributeHandler(userAttributeService)
 	adminHandlers := handler.ProvideAdminHandlers(dashboardHandler, adminUserHandler, groupHandler, accountHandler, oAuthHandler, openAIOAuthHandler, geminiOAuthHandler, antigravityOAuthHandler, proxyHandler, adminRedeemHandler, settingHandler, systemHandler, adminSubscriptionHandler, adminUsageHandler, userAttributeHandler)
-	pricingRemoteClient := repository.NewPricingRemoteClient()
+	pricingRemoteClient := repository.NewPricingRemoteClient(configConfig)
 	pricingService, err := service.ProvidePricingService(configConfig, pricingRemoteClient)
 	if err != nil {
 		return nil, err
@@ -136,10 +136,10 @@ func initializeApplication(buildInfo handler.BuildInfo) (*Application, error) {
 	timingWheelService := service.ProvideTimingWheelService()
 	deferredService := service.ProvideDeferredService(accountRepository, timingWheelService)
 	gatewayService := service.NewGatewayService(accountRepository, groupRepository, usageLogRepository, userRepository, userSubscriptionRepository, gatewayCache, configConfig, concurrencyService, billingService, rateLimitService, billingCacheService, identityService, httpUpstream, deferredService)
-	geminiMessagesCompatService := service.NewGeminiMessagesCompatService(accountRepository, groupRepository, gatewayCache, geminiTokenProvider, rateLimitService, httpUpstream, antigravityGatewayService)
-	gatewayHandler := handler.NewGatewayHandler(gatewayService, geminiMessagesCompatService, antigravityGatewayService, userService, concurrencyService, billingCacheService)
+	geminiMessagesCompatService := service.NewGeminiMessagesCompatService(accountRepository, groupRepository, gatewayCache, geminiTokenProvider, rateLimitService, httpUpstream, antigravityGatewayService, configConfig)
+	gatewayHandler := handler.NewGatewayHandler(gatewayService, geminiMessagesCompatService, antigravityGatewayService, userService, concurrencyService, billingCacheService, configConfig)
 	openAIGatewayService := service.NewOpenAIGatewayService(accountRepository, usageLogRepository, userRepository, userSubscriptionRepository, gatewayCache, configConfig, concurrencyService, billingService, rateLimitService, billingCacheService, httpUpstream, deferredService)
-	openAIGatewayHandler := handler.NewOpenAIGatewayHandler(openAIGatewayService, concurrencyService, billingCacheService)
+	openAIGatewayHandler := handler.NewOpenAIGatewayHandler(openAIGatewayService, concurrencyService, billingCacheService, configConfig)
 	handlerSettingHandler := handler.ProvideSettingHandler(settingService, buildInfo)
 	handlers := handler.ProvideHandlers(authHandler, userHandler, apiKeyHandler, usageHandler, redeemHandler, subscriptionHandler, adminHandlers, gatewayHandler, openAIGatewayHandler, handlerSettingHandler)
 	jwtAuthMiddleware := middleware.NewJWTAuthMiddleware(authService, userService)
--- a/backend/internal/config/config.go
+++ b/backend/internal/config/config.go
@@ -2,7 +2,10 @@
 package config

 import (
+	"crypto/rand"
+	"encoding/hex"
 	"fmt"
+	"log"
 	"strings"
 	"time"

@@ -14,6 +17,8 @@ const (
 	RunModeSimple   = "simple"
 )

+const DefaultCSPPolicy = "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data: https:; font-src 'self' data:; connect-src 'self' https:; frame-ancestors 'none'; base-uri 'self'; form-action 'self'"
+
 // 连接池隔离策略常量
 // 用于控制上游 HTTP 连接池的隔离粒度，影响连接复用和资源消耗
 const (
@@ -30,6 +35,10 @@ const (

 type Config struct {
 	Server       ServerConfig       `mapstructure:"server"`
+	CORS         CORSConfig         `mapstructure:"cors"`
+	Security     SecurityConfig     `mapstructure:"security"`
+	Billing      BillingConfig      `mapstructure:"billing"`
+	Turnstile    TurnstileConfig    `mapstructure:"turnstile"`
 	Database     DatabaseConfig     `mapstructure:"database"`
 	Redis        RedisConfig        `mapstructure:"redis"`
 	JWT          JWTConfig          `mapstructure:"jwt"`
@@ -37,6 +46,7 @@ type Config struct {
 	RateLimit    RateLimitConfig    `mapstructure:"rate_limit"`
 	Pricing      PricingConfig      `mapstructure:"pricing"`
 	Gateway      GatewayConfig      `mapstructure:"gateway"`
+	Concurrency  ConcurrencyConfig  `mapstructure:"concurrency"`
 	TokenRefresh TokenRefreshConfig `mapstructure:"token_refresh"`
 	RunMode      string             `mapstructure:"run_mode" yaml:"run_mode"`
 	Timezone     string             `mapstructure:"timezone"` // e.g. "Asia/Shanghai", "UTC"
@@ -95,11 +105,61 @@ type PricingConfig struct {
 }

 type ServerConfig struct {
-	Host              string `mapstructure:"host"`
-	Port              int    `mapstructure:"port"`
-	Mode              string `mapstructure:"mode"`                // debug/release
-	ReadHeaderTimeout int    `mapstructure:"read_header_timeout"` // 读取请求头超时（秒）
-	IdleTimeout       int    `mapstructure:"idle_timeout"`        // 空闲连接超时（秒）
+	Host              string   `mapstructure:"host"`
+	Port              int      `mapstructure:"port"`
+	Mode              string   `mapstructure:"mode"`                // debug/release
+	ReadHeaderTimeout int      `mapstructure:"read_header_timeout"` // 读取请求头超时（秒）
+	IdleTimeout       int      `mapstructure:"idle_timeout"`        // 空闲连接超时（秒）
+	TrustedProxies    []string `mapstructure:"trusted_proxies"`     // 可信代理列表（CIDR/IP）
+}
+
+type CORSConfig struct {
+	AllowedOrigins   []string `mapstructure:"allowed_origins"`
+	AllowCredentials bool     `mapstructure:"allow_credentials"`
+}
+
+type SecurityConfig struct {
+	URLAllowlist    URLAllowlistConfig   `mapstructure:"url_allowlist"`
+	ResponseHeaders ResponseHeaderConfig `mapstructure:"response_headers"`
+	CSP             CSPConfig            `mapstructure:"csp"`
+	ProxyProbe      ProxyProbeConfig     `mapstructure:"proxy_probe"`
+}
+
+type URLAllowlistConfig struct {
+	UpstreamHosts     []string `mapstructure:"upstream_hosts"`
+	PricingHosts      []string `mapstructure:"pricing_hosts"`
+	CRSHosts          []string `mapstructure:"crs_hosts"`
+	AllowPrivateHosts bool     `mapstructure:"allow_private_hosts"`
+}
+
+type ResponseHeaderConfig struct {
+	AdditionalAllowed []string `mapstructure:"additional_allowed"`
+	ForceRemove       []string `mapstructure:"force_remove"`
+}
+
+type CSPConfig struct {
+	Enabled bool   `mapstructure:"enabled"`
+	Policy  string `mapstructure:"policy"`
+}
+
+type ProxyProbeConfig struct {
+	InsecureSkipVerify bool `mapstructure:"insecure_skip_verify"`
+}
+
+type BillingConfig struct {
+	CircuitBreaker CircuitBreakerConfig `mapstructure:"circuit_breaker"`
+}
+
+type CircuitBreakerConfig struct {
+	Enabled             bool `mapstructure:"enabled"`
+	FailureThreshold    int  `mapstructure:"failure_threshold"`
+	ResetTimeoutSeconds int  `mapstructure:"reset_timeout_seconds"`
+	HalfOpenRequests    int  `mapstructure:"half_open_requests"`
+}
+
+type ConcurrencyConfig struct {
+	// PingInterval: 并发等待期间的 SSE ping 间隔（秒）
+	PingInterval int `mapstructure:"ping_interval"`
 }

 // GatewayConfig API网关相关配置
@@ -134,6 +194,13 @@ type GatewayConfig struct {
 	// 应大于最长 LLM 请求时间，防止请求完成前槽位过期
 	ConcurrencySlotTTLMinutes int `mapstructure:"concurrency_slot_ttl_minutes"`

+	// StreamDataIntervalTimeout: 流数据间隔超时（秒），0表示禁用
+	StreamDataIntervalTimeout int `mapstructure:"stream_data_interval_timeout"`
+	// StreamKeepaliveInterval: 流式 keepalive 间隔（秒），0表示禁用
+	StreamKeepaliveInterval int `mapstructure:"stream_keepalive_interval"`
+	// MaxLineSize: 上游 SSE 单行最大字节数（0使用默认值）
+	MaxLineSize int `mapstructure:"max_line_size"`
+
 	// 是否记录上游错误响应体摘要（避免输出请求内容）
 	LogUpstreamErrorBody bool `mapstructure:"log_upstream_error_body"`
 	// 上游错误响应体记录最大字节数（超过会截断）
@@ -237,6 +304,10 @@ type JWTConfig struct {
 	ExpireHour int    `mapstructure:"expire_hour"`
 }

+type TurnstileConfig struct {
+	Required bool `mapstructure:"required"`
+}
+
 type DefaultConfig struct {
 	AdminEmail      string  `mapstructure:"admin_email"`
 	AdminPassword   string  `mapstructure:"admin_password"`
@@ -287,11 +358,39 @@ func Load() (*Config, error) {
 	}

 	cfg.RunMode = NormalizeRunMode(cfg.RunMode)
+	cfg.Server.Mode = strings.ToLower(strings.TrimSpace(cfg.Server.Mode))
+	if cfg.Server.Mode == "" {
+		cfg.Server.Mode = "debug"
+	}
+	cfg.JWT.Secret = strings.TrimSpace(cfg.JWT.Secret)
+	cfg.CORS.AllowedOrigins = normalizeStringSlice(cfg.CORS.AllowedOrigins)
+	cfg.Security.ResponseHeaders.AdditionalAllowed = normalizeStringSlice(cfg.Security.ResponseHeaders.AdditionalAllowed)
+	cfg.Security.ResponseHeaders.ForceRemove = normalizeStringSlice(cfg.Security.ResponseHeaders.ForceRemove)
+	cfg.Security.CSP.Policy = strings.TrimSpace(cfg.Security.CSP.Policy)
+
+	if cfg.Server.Mode != "release" && cfg.JWT.Secret == "" {
+		secret, err := generateJWTSecret(64)
+		if err != nil {
+			return nil, fmt.Errorf("generate jwt secret error: %w", err)
+		}
+		cfg.JWT.Secret = secret
+		log.Println("Warning: JWT secret auto-generated for non-release mode. Do not use in production.")
+	}

 	if err := cfg.Validate(); err != nil {
 		return nil, fmt.Errorf("validate config error: %w", err)
 	}

+	if cfg.Server.Mode != "release" && cfg.JWT.Secret != "" && isWeakJWTSecret(cfg.JWT.Secret) {
+		log.Println("Warning: JWT secret appears weak; use a 32+ character random secret in production.")
+	}
+	if len(cfg.Security.ResponseHeaders.AdditionalAllowed) > 0 || len(cfg.Security.ResponseHeaders.ForceRemove) > 0 {
+		log.Printf("AUDIT: response header policy configured additional_allowed=%v force_remove=%v",
+			cfg.Security.ResponseHeaders.AdditionalAllowed,
+			cfg.Security.ResponseHeaders.ForceRemove,
+		)
+	}
+
 	return &cfg, nil
 }

@@ -304,6 +403,39 @@ func setDefaults() {
 	viper.SetDefault("server.mode", "debug")
 	viper.SetDefault("server.read_header_timeout", 30) // 30秒读取请求头
 	viper.SetDefault("server.idle_timeout", 120)       // 120秒空闲超时
+	viper.SetDefault("server.trusted_proxies", []string{})
+
+	// CORS
+	viper.SetDefault("cors.allowed_origins", []string{})
+	viper.SetDefault("cors.allow_credentials", true)
+
+	// Security
+	viper.SetDefault("security.url_allowlist.upstream_hosts", []string{
+		"api.openai.com",
+		"api.anthropic.com",
+		"generativelanguage.googleapis.com",
+		"cloudcode-pa.googleapis.com",
+		"*.openai.azure.com",
+	})
+	viper.SetDefault("security.url_allowlist.pricing_hosts", []string{
+		"raw.githubusercontent.com",
+	})
+	viper.SetDefault("security.url_allowlist.crs_hosts", []string{})
+	viper.SetDefault("security.url_allowlist.allow_private_hosts", false)
+	viper.SetDefault("security.response_headers.additional_allowed", []string{})
+	viper.SetDefault("security.response_headers.force_remove", []string{})
+	viper.SetDefault("security.csp.enabled", true)
+	viper.SetDefault("security.csp.policy", DefaultCSPPolicy)
+	viper.SetDefault("security.proxy_probe.insecure_skip_verify", false)
+
+	// Billing
+	viper.SetDefault("billing.circuit_breaker.enabled", true)
+	viper.SetDefault("billing.circuit_breaker.failure_threshold", 5)
+	viper.SetDefault("billing.circuit_breaker.reset_timeout_seconds", 30)
+	viper.SetDefault("billing.circuit_breaker.half_open_requests", 3)
+
+	// Turnstile
+	viper.SetDefault("turnstile.required", false)

 	// Database
 	viper.SetDefault("database.host", "localhost")
@@ -329,7 +461,7 @@ func setDefaults() {
 	viper.SetDefault("redis.min_idle_conns", 10)

 	// JWT
-	viper.SetDefault("jwt.secret", "change-me-in-production")
+	viper.SetDefault("jwt.secret", "")
 	viper.SetDefault("jwt.expire_hour", 24)

 	// Default
@@ -357,7 +489,7 @@ func setDefaults() {
 	viper.SetDefault("timezone", "Asia/Shanghai")

 	// Gateway
-	viper.SetDefault("gateway.response_header_timeout", 300) // 300秒(5分钟)等待上游响应头，LLM高负载时可能排队较久
+	viper.SetDefault("gateway.response_header_timeout", 600) // 600秒(10分钟)等待上游响应头，LLM高负载时可能排队较久
 	viper.SetDefault("gateway.log_upstream_error_body", false)
 	viper.SetDefault("gateway.log_upstream_error_body_max_bytes", 2048)
 	viper.SetDefault("gateway.inject_beta_for_apikey", false)
@@ -365,19 +497,23 @@ func setDefaults() {
 	viper.SetDefault("gateway.max_body_size", int64(100*1024*1024))
 	viper.SetDefault("gateway.connection_pool_isolation", ConnectionPoolIsolationAccountProxy)
 	// HTTP 上游连接池配置（针对 5000+ 并发用户优化）
-	viper.SetDefault("gateway.max_idle_conns", 240)            // 最大空闲连接总数（HTTP/2 场景默认）
-	viper.SetDefault("gateway.max_idle_conns_per_host", 120)   // 每主机最大空闲连接（HTTP/2 场景默认）
-	viper.SetDefault("gateway.max_conns_per_host", 240)        // 每主机最大连接数（含活跃，HTTP/2 场景默认）
-	viper.SetDefault("gateway.idle_conn_timeout_seconds", 300) // 空闲连接超时（秒）
+	viper.SetDefault("gateway.max_idle_conns", 240)           // 最大空闲连接总数（HTTP/2 场景默认）
+	viper.SetDefault("gateway.max_idle_conns_per_host", 120)  // 每主机最大空闲连接（HTTP/2 场景默认）
+	viper.SetDefault("gateway.max_conns_per_host", 240)       // 每主机最大连接数（含活跃，HTTP/2 场景默认）
+	viper.SetDefault("gateway.idle_conn_timeout_seconds", 90) // 空闲连接超时（秒）
 	viper.SetDefault("gateway.max_upstream_clients", 5000)
 	viper.SetDefault("gateway.client_idle_ttl_seconds", 900)
-	viper.SetDefault("gateway.concurrency_slot_ttl_minutes", 15) // 并发槽位过期时间（支持超长请求）
+	viper.SetDefault("gateway.concurrency_slot_ttl_minutes", 30) // 并发槽位过期时间（支持超长请求）
+	viper.SetDefault("gateway.stream_data_interval_timeout", 180)
+	viper.SetDefault("gateway.stream_keepalive_interval", 10)
+	viper.SetDefault("gateway.max_line_size", 10*1024*1024)
 	viper.SetDefault("gateway.scheduling.sticky_session_max_waiting", 3)
 	viper.SetDefault("gateway.scheduling.sticky_session_wait_timeout", 45*time.Second)
 	viper.SetDefault("gateway.scheduling.fallback_wait_timeout", 30*time.Second)
 	viper.SetDefault("gateway.scheduling.fallback_max_waiting", 100)
 	viper.SetDefault("gateway.scheduling.load_batch_enabled", true)
 	viper.SetDefault("gateway.scheduling.slot_cleanup_interval", 30*time.Second)
+	viper.SetDefault("concurrency.ping_interval", 10)

 	// TokenRefresh
 	viper.SetDefault("token_refresh.enabled", true)
@@ -396,11 +532,39 @@ func setDefaults() {
 }

 func (c *Config) Validate() error {
-	if c.JWT.Secret == "" {
-		return fmt.Errorf("jwt.secret is required")
+	if c.Server.Mode == "release" {
+		if c.JWT.Secret == "" {
+			return fmt.Errorf("jwt.secret is required in release mode")
+		}
+		if len(c.JWT.Secret) < 32 {
+			return fmt.Errorf("jwt.secret must be at least 32 characters")
+		}
+		if isWeakJWTSecret(c.JWT.Secret) {
+			return fmt.Errorf("jwt.secret is too weak")
+		}
 	}
-	if c.JWT.Secret == "change-me-in-production" && c.Server.Mode == "release" {
-		return fmt.Errorf("jwt.secret must be changed in production")
+	if c.JWT.ExpireHour <= 0 {
+		return fmt.Errorf("jwt.expire_hour must be positive")
+	}
+	if c.JWT.ExpireHour > 168 {
+		return fmt.Errorf("jwt.expire_hour must be <= 168 (7 days)")
+	}
+	if c.JWT.ExpireHour > 24 {
+		log.Printf("Warning: jwt.expire_hour is %d hours (> 24). Consider shorter expiration for security.", c.JWT.ExpireHour)
+	}
+	if c.Security.CSP.Enabled && strings.TrimSpace(c.Security.CSP.Policy) == "" {
+		return fmt.Errorf("security.csp.policy is required when CSP is enabled")
+	}
+	if c.Billing.CircuitBreaker.Enabled {
+		if c.Billing.CircuitBreaker.FailureThreshold <= 0 {
+			return fmt.Errorf("billing.circuit_breaker.failure_threshold must be positive")
+		}
+		if c.Billing.CircuitBreaker.ResetTimeoutSeconds <= 0 {
+			return fmt.Errorf("billing.circuit_breaker.reset_timeout_seconds must be positive")
+		}
+		if c.Billing.CircuitBreaker.HalfOpenRequests <= 0 {
+			return fmt.Errorf("billing.circuit_breaker.half_open_requests must be positive")
+		}
 	}
 	if c.Database.MaxOpenConns <= 0 {
 		return fmt.Errorf("database.max_open_conns must be positive")
@@ -458,6 +622,9 @@ func (c *Config) Validate() error {
 	if c.Gateway.IdleConnTimeoutSeconds <= 0 {
 		return fmt.Errorf("gateway.idle_conn_timeout_seconds must be positive")
 	}
+	if c.Gateway.IdleConnTimeoutSeconds > 180 {
+		log.Printf("Warning: gateway.idle_conn_timeout_seconds is %d (> 180). Consider 60-120 seconds for better connection reuse.", c.Gateway.IdleConnTimeoutSeconds)
+	}
 	if c.Gateway.MaxUpstreamClients <= 0 {
 		return fmt.Errorf("gateway.max_upstream_clients must be positive")
 	}
@@ -467,6 +634,26 @@ func (c *Config) Validate() error {
 	if c.Gateway.ConcurrencySlotTTLMinutes <= 0 {
 		return fmt.Errorf("gateway.concurrency_slot_ttl_minutes must be positive")
 	}
+	if c.Gateway.StreamDataIntervalTimeout < 0 {
+		return fmt.Errorf("gateway.stream_data_interval_timeout must be non-negative")
+	}
+	if c.Gateway.StreamDataIntervalTimeout != 0 &&
+		(c.Gateway.StreamDataIntervalTimeout < 30 || c.Gateway.StreamDataIntervalTimeout > 300) {
+		return fmt.Errorf("gateway.stream_data_interval_timeout must be 0 or between 30-300 seconds")
+	}
+	if c.Gateway.StreamKeepaliveInterval < 0 {
+		return fmt.Errorf("gateway.stream_keepalive_interval must be non-negative")
+	}
+	if c.Gateway.StreamKeepaliveInterval != 0 &&
+		(c.Gateway.StreamKeepaliveInterval < 5 || c.Gateway.StreamKeepaliveInterval > 30) {
+		return fmt.Errorf("gateway.stream_keepalive_interval must be 0 or between 5-30 seconds")
+	}
+	if c.Gateway.MaxLineSize < 0 {
+		return fmt.Errorf("gateway.max_line_size must be non-negative")
+	}
+	if c.Gateway.MaxLineSize != 0 && c.Gateway.MaxLineSize < 1024*1024 {
+		return fmt.Errorf("gateway.max_line_size must be at least 1MB")
+	}
 	if c.Gateway.Scheduling.StickySessionMaxWaiting <= 0 {
 		return fmt.Errorf("gateway.scheduling.sticky_session_max_waiting must be positive")
 	}
@@ -482,9 +669,57 @@ func (c *Config) Validate() error {
 	if c.Gateway.Scheduling.SlotCleanupInterval < 0 {
 		return fmt.Errorf("gateway.scheduling.slot_cleanup_interval must be non-negative")
 	}
+	if c.Concurrency.PingInterval < 5 || c.Concurrency.PingInterval > 30 {
+		return fmt.Errorf("concurrency.ping_interval must be between 5-30 seconds")
+	}
 	return nil
 }

+func normalizeStringSlice(values []string) []string {
+	if len(values) == 0 {
+		return values
+	}
+	normalized := make([]string, 0, len(values))
+	for _, v := range values {
+		trimmed := strings.TrimSpace(v)
+		if trimmed == "" {
+			continue
+		}
+		normalized = append(normalized, trimmed)
+	}
+	return normalized
+}
+
+func isWeakJWTSecret(secret string) bool {
+	lower := strings.ToLower(strings.TrimSpace(secret))
+	if lower == "" {
+		return true
+	}
+	weak := map[string]struct{}{
+		"change-me-in-production": {},
+		"changeme":                {},
+		"secret":                  {},
+		"password":                {},
+		"123456":                  {},
+		"12345678":                {},
+		"admin":                   {},
+		"jwt-secret":              {},
+	}
+	_, exists := weak[lower]
+	return exists
+}
+
+func generateJWTSecret(byteLength int) (string, error) {
+	if byteLength <= 0 {
+		byteLength = 32
+	}
+	buf := make([]byte, byteLength)
+	if _, err := rand.Read(buf); err != nil {
+		return "", err
+	}
+	return hex.EncodeToString(buf), nil
+}
+
 // GetServerAddress returns the server address (host:port) from config file or environment variable.
 // This is a lightweight function that can be used before full config validation,
 // such as during setup wizard startup.
--- a/backend/internal/handler/admin/setting_handler.go
+++ b/backend/internal/handler/admin/setting_handler.go
@@ -1,8 +1,12 @@
 package admin

 import (
+	"log"
+	"time"
+
 	"github.com/Wei-Shaw/sub2api/internal/handler/dto"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/response"
+	"github.com/Wei-Shaw/sub2api/internal/server/middleware"
 	"github.com/Wei-Shaw/sub2api/internal/service"

 	"github.com/gin-gonic/gin"
@@ -34,31 +38,31 @@ func (h *SettingHandler) GetSettings(c *gin.Context) {
 	}

 	response.Success(c, dto.SystemSettings{
-		RegistrationEnabled:      settings.RegistrationEnabled,
-		EmailVerifyEnabled:       settings.EmailVerifyEnabled,
-		SMTPHost:                 settings.SMTPHost,
-		SMTPPort:                 settings.SMTPPort,
-		SMTPUsername:             settings.SMTPUsername,
-		SMTPPassword:             settings.SMTPPassword,
-		SMTPFrom:                 settings.SMTPFrom,
-		SMTPFromName:             settings.SMTPFromName,
-		SMTPUseTLS:               settings.SMTPUseTLS,
-		TurnstileEnabled:         settings.TurnstileEnabled,
-		TurnstileSiteKey:         settings.TurnstileSiteKey,
-		TurnstileSecretKey:       settings.TurnstileSecretKey,
-		SiteName:                 settings.SiteName,
-		SiteLogo:                 settings.SiteLogo,
-		SiteSubtitle:             settings.SiteSubtitle,
-		APIBaseURL:               settings.APIBaseURL,
-		ContactInfo:              settings.ContactInfo,
-		DocURL:                   settings.DocURL,
-		DefaultConcurrency:       settings.DefaultConcurrency,
-		DefaultBalance:           settings.DefaultBalance,
-		EnableModelFallback:      settings.EnableModelFallback,
-		FallbackModelAnthropic:   settings.FallbackModelAnthropic,
-		FallbackModelOpenAI:      settings.FallbackModelOpenAI,
-		FallbackModelGemini:      settings.FallbackModelGemini,
-		FallbackModelAntigravity: settings.FallbackModelAntigravity,
+		RegistrationEnabled:          settings.RegistrationEnabled,
+		EmailVerifyEnabled:           settings.EmailVerifyEnabled,
+		SMTPHost:                     settings.SMTPHost,
+		SMTPPort:                     settings.SMTPPort,
+		SMTPUsername:                 settings.SMTPUsername,
+		SMTPPasswordConfigured:       settings.SMTPPasswordConfigured,
+		SMTPFrom:                     settings.SMTPFrom,
+		SMTPFromName:                 settings.SMTPFromName,
+		SMTPUseTLS:                   settings.SMTPUseTLS,
+		TurnstileEnabled:             settings.TurnstileEnabled,
+		TurnstileSiteKey:             settings.TurnstileSiteKey,
+		TurnstileSecretKeyConfigured: settings.TurnstileSecretKeyConfigured,
+		SiteName:                     settings.SiteName,
+		SiteLogo:                     settings.SiteLogo,
+		SiteSubtitle:                 settings.SiteSubtitle,
+		APIBaseURL:                   settings.APIBaseURL,
+		ContactInfo:                  settings.ContactInfo,
+		DocURL:                       settings.DocURL,
+		DefaultConcurrency:           settings.DefaultConcurrency,
+		DefaultBalance:               settings.DefaultBalance,
+		EnableModelFallback:          settings.EnableModelFallback,
+		FallbackModelAnthropic:       settings.FallbackModelAnthropic,
+		FallbackModelOpenAI:          settings.FallbackModelOpenAI,
+		FallbackModelGemini:          settings.FallbackModelGemini,
+		FallbackModelAntigravity:     settings.FallbackModelAntigravity,
 	})
 }

@@ -111,6 +115,12 @@ func (h *SettingHandler) UpdateSettings(c *gin.Context) {
 		return
 	}

+	previousSettings, err := h.settingService.GetAllSettings(c.Request.Context())
+	if err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+
 	// 验证参数
 	if req.DefaultConcurrency < 1 {
 		req.DefaultConcurrency = 1
@@ -185,6 +195,8 @@ func (h *SettingHandler) UpdateSettings(c *gin.Context) {
 		return
 	}

+	h.auditSettingsUpdate(c, previousSettings, settings, req)
+
 	// 重新获取设置返回
 	updatedSettings, err := h.settingService.GetAllSettings(c.Request.Context())
 	if err != nil {
@@ -193,34 +205,134 @@ func (h *SettingHandler) UpdateSettings(c *gin.Context) {
 	}

 	response.Success(c, dto.SystemSettings{
-		RegistrationEnabled:      updatedSettings.RegistrationEnabled,
-		EmailVerifyEnabled:       updatedSettings.EmailVerifyEnabled,
-		SMTPHost:                 updatedSettings.SMTPHost,
-		SMTPPort:                 updatedSettings.SMTPPort,
-		SMTPUsername:             updatedSettings.SMTPUsername,
-		SMTPPassword:             updatedSettings.SMTPPassword,
-		SMTPFrom:                 updatedSettings.SMTPFrom,
-		SMTPFromName:             updatedSettings.SMTPFromName,
-		SMTPUseTLS:               updatedSettings.SMTPUseTLS,
-		TurnstileEnabled:         updatedSettings.TurnstileEnabled,
-		TurnstileSiteKey:         updatedSettings.TurnstileSiteKey,
-		TurnstileSecretKey:       updatedSettings.TurnstileSecretKey,
-		SiteName:                 updatedSettings.SiteName,
-		SiteLogo:                 updatedSettings.SiteLogo,
-		SiteSubtitle:             updatedSettings.SiteSubtitle,
-		APIBaseURL:               updatedSettings.APIBaseURL,
-		ContactInfo:              updatedSettings.ContactInfo,
-		DocURL:                   updatedSettings.DocURL,
-		DefaultConcurrency:       updatedSettings.DefaultConcurrency,
-		DefaultBalance:           updatedSettings.DefaultBalance,
-		EnableModelFallback:      updatedSettings.EnableModelFallback,
-		FallbackModelAnthropic:   updatedSettings.FallbackModelAnthropic,
-		FallbackModelOpenAI:      updatedSettings.FallbackModelOpenAI,
-		FallbackModelGemini:      updatedSettings.FallbackModelGemini,
-		FallbackModelAntigravity: updatedSettings.FallbackModelAntigravity,
+		RegistrationEnabled:          updatedSettings.RegistrationEnabled,
+		EmailVerifyEnabled:           updatedSettings.EmailVerifyEnabled,
+		SMTPHost:                     updatedSettings.SMTPHost,
+		SMTPPort:                     updatedSettings.SMTPPort,
+		SMTPUsername:                 updatedSettings.SMTPUsername,
+		SMTPPasswordConfigured:       updatedSettings.SMTPPasswordConfigured,
+		SMTPFrom:                     updatedSettings.SMTPFrom,
+		SMTPFromName:                 updatedSettings.SMTPFromName,
+		SMTPUseTLS:                   updatedSettings.SMTPUseTLS,
+		TurnstileEnabled:             updatedSettings.TurnstileEnabled,
+		TurnstileSiteKey:             updatedSettings.TurnstileSiteKey,
+		TurnstileSecretKeyConfigured: updatedSettings.TurnstileSecretKeyConfigured,
+		SiteName:                     updatedSettings.SiteName,
+		SiteLogo:                     updatedSettings.SiteLogo,
+		SiteSubtitle:                 updatedSettings.SiteSubtitle,
+		APIBaseURL:                   updatedSettings.APIBaseURL,
+		ContactInfo:                  updatedSettings.ContactInfo,
+		DocURL:                       updatedSettings.DocURL,
+		DefaultConcurrency:           updatedSettings.DefaultConcurrency,
+		DefaultBalance:               updatedSettings.DefaultBalance,
+		EnableModelFallback:          updatedSettings.EnableModelFallback,
+		FallbackModelAnthropic:       updatedSettings.FallbackModelAnthropic,
+		FallbackModelOpenAI:          updatedSettings.FallbackModelOpenAI,
+		FallbackModelGemini:          updatedSettings.FallbackModelGemini,
+		FallbackModelAntigravity:     updatedSettings.FallbackModelAntigravity,
 	})
 }

+func (h *SettingHandler) auditSettingsUpdate(c *gin.Context, before *service.SystemSettings, after *service.SystemSettings, req UpdateSettingsRequest) {
+	if before == nil || after == nil {
+		return
+	}
+
+	changed := diffSettings(before, after, req)
+	if len(changed) == 0 {
+		return
+	}
+
+	subject, _ := middleware.GetAuthSubjectFromContext(c)
+	role, _ := middleware.GetUserRoleFromContext(c)
+	log.Printf("AUDIT: settings updated at=%s user_id=%d role=%s changed=%v",
+		time.Now().UTC().Format(time.RFC3339),
+		subject.UserID,
+		role,
+		changed,
+	)
+}
+
+func diffSettings(before *service.SystemSettings, after *service.SystemSettings, req UpdateSettingsRequest) []string {
+	changed := make([]string, 0, 20)
+	if before.RegistrationEnabled != after.RegistrationEnabled {
+		changed = append(changed, "registration_enabled")
+	}
+	if before.EmailVerifyEnabled != after.EmailVerifyEnabled {
+		changed = append(changed, "email_verify_enabled")
+	}
+	if before.SMTPHost != after.SMTPHost {
+		changed = append(changed, "smtp_host")
+	}
+	if before.SMTPPort != after.SMTPPort {
+		changed = append(changed, "smtp_port")
+	}
+	if before.SMTPUsername != after.SMTPUsername {
+		changed = append(changed, "smtp_username")
+	}
+	if req.SMTPPassword != "" {
+		changed = append(changed, "smtp_password")
+	}
+	if before.SMTPFrom != after.SMTPFrom {
+		changed = append(changed, "smtp_from_email")
+	}
+	if before.SMTPFromName != after.SMTPFromName {
+		changed = append(changed, "smtp_from_name")
+	}
+	if before.SMTPUseTLS != after.SMTPUseTLS {
+		changed = append(changed, "smtp_use_tls")
+	}
+	if before.TurnstileEnabled != after.TurnstileEnabled {
+		changed = append(changed, "turnstile_enabled")
+	}
+	if before.TurnstileSiteKey != after.TurnstileSiteKey {
+		changed = append(changed, "turnstile_site_key")
+	}
+	if req.TurnstileSecretKey != "" {
+		changed = append(changed, "turnstile_secret_key")
+	}
+	if before.SiteName != after.SiteName {
+		changed = append(changed, "site_name")
+	}
+	if before.SiteLogo != after.SiteLogo {
+		changed = append(changed, "site_logo")
+	}
+	if before.SiteSubtitle != after.SiteSubtitle {
+		changed = append(changed, "site_subtitle")
+	}
+	if before.APIBaseURL != after.APIBaseURL {
+		changed = append(changed, "api_base_url")
+	}
+	if before.ContactInfo != after.ContactInfo {
+		changed = append(changed, "contact_info")
+	}
+	if before.DocURL != after.DocURL {
+		changed = append(changed, "doc_url")
+	}
+	if before.DefaultConcurrency != after.DefaultConcurrency {
+		changed = append(changed, "default_concurrency")
+	}
+	if before.DefaultBalance != after.DefaultBalance {
+		changed = append(changed, "default_balance")
+	}
+	if before.EnableModelFallback != after.EnableModelFallback {
+		changed = append(changed, "enable_model_fallback")
+	}
+	if before.FallbackModelAnthropic != after.FallbackModelAnthropic {
+		changed = append(changed, "fallback_model_anthropic")
+	}
+	if before.FallbackModelOpenAI != after.FallbackModelOpenAI {
+		changed = append(changed, "fallback_model_openai")
+	}
+	if before.FallbackModelGemini != after.FallbackModelGemini {
+		changed = append(changed, "fallback_model_gemini")
+	}
+	if before.FallbackModelAntigravity != after.FallbackModelAntigravity {
+		changed = append(changed, "fallback_model_antigravity")
+	}
+	return changed
+}
+
 // TestSMTPRequest 测试SMTP连接请求
 type TestSMTPRequest struct {
 	SMTPHost     string `json:"smtp_host" binding:"required"`
--- a/backend/internal/handler/dto/settings.go
+++ b/backend/internal/handler/dto/settings.go
@@ -5,17 +5,17 @@ type SystemSettings struct {
 	RegistrationEnabled bool `json:"registration_enabled"`
 	EmailVerifyEnabled  bool `json:"email_verify_enabled"`

-	SMTPHost     string `json:"smtp_host"`
-	SMTPPort     int    `json:"smtp_port"`
-	SMTPUsername string `json:"smtp_username"`
-	SMTPPassword string `json:"smtp_password,omitempty"`
-	SMTPFrom     string `json:"smtp_from_email"`
-	SMTPFromName string `json:"smtp_from_name"`
-	SMTPUseTLS   bool   `json:"smtp_use_tls"`
+	SMTPHost               string `json:"smtp_host"`
+	SMTPPort               int    `json:"smtp_port"`
+	SMTPUsername           string `json:"smtp_username"`
+	SMTPPasswordConfigured bool   `json:"smtp_password_configured"`
+	SMTPFrom               string `json:"smtp_from_email"`
+	SMTPFromName           string `json:"smtp_from_name"`
+	SMTPUseTLS             bool   `json:"smtp_use_tls"`

-	TurnstileEnabled   bool   `json:"turnstile_enabled"`
-	TurnstileSiteKey   string `json:"turnstile_site_key"`
-	TurnstileSecretKey string `json:"turnstile_secret_key,omitempty"`
+	TurnstileEnabled             bool   `json:"turnstile_enabled"`
+	TurnstileSiteKey             string `json:"turnstile_site_key"`
+	TurnstileSecretKeyConfigured bool   `json:"turnstile_secret_key_configured"`

 	SiteName     string `json:"site_name"`
 	SiteLogo     string `json:"site_logo"`
--- a/backend/internal/handler/gateway_handler.go
+++ b/backend/internal/handler/gateway_handler.go
@@ -11,8 +11,10 @@ import (
 	"strings"
 	"time"

+	"github.com/Wei-Shaw/sub2api/internal/config"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/antigravity"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/claude"
+	pkgerrors "github.com/Wei-Shaw/sub2api/internal/pkg/errors"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/openai"
 	middleware2 "github.com/Wei-Shaw/sub2api/internal/server/middleware"
 	"github.com/Wei-Shaw/sub2api/internal/service"
@@ -38,14 +40,19 @@ func NewGatewayHandler(
 	userService *service.UserService,
 	concurrencyService *service.ConcurrencyService,
 	billingCacheService *service.BillingCacheService,
+	cfg *config.Config,
 ) *GatewayHandler {
+	pingInterval := time.Duration(0)
+	if cfg != nil {
+		pingInterval = time.Duration(cfg.Concurrency.PingInterval) * time.Second
+	}
 	return &GatewayHandler{
 		gatewayService:            gatewayService,
 		geminiCompatService:       geminiCompatService,
 		antigravityGatewayService: antigravityGatewayService,
 		userService:               userService,
 		billingCacheService:       billingCacheService,
-		concurrencyHelper:         NewConcurrencyHelper(concurrencyService, SSEPingFormatClaude),
+		concurrencyHelper:         NewConcurrencyHelper(concurrencyService, SSEPingFormatClaude, pingInterval),
 	}
 }

@@ -121,6 +128,8 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 		h.handleConcurrencyError(c, err, "user", streamStarted)
 		return
 	}
+	// 在请求结束或 Context 取消时确保释放槽位，避免客户端断开造成泄漏
+	userReleaseFunc = wrapReleaseOnDone(c.Request.Context(), userReleaseFunc)
 	if userReleaseFunc != nil {
 		defer userReleaseFunc()
 	}
@@ -128,7 +137,8 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 	// 2. 【新增】Wait后二次检查余额/订阅
 	if err := h.billingCacheService.CheckBillingEligibility(c.Request.Context(), apiKey.User, apiKey, apiKey.Group, subscription); err != nil {
 		log.Printf("Billing eligibility check failed after wait: %v", err)
-		h.handleStreamingAwareError(c, http.StatusForbidden, "billing_error", err.Error(), streamStarted)
+		status, code, message := billingErrorDetails(err)
+		h.handleStreamingAwareError(c, status, code, message, streamStarted)
 		return
 	}

@@ -220,6 +230,9 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 					log.Printf("Bind sticky session failed: %v", err)
 				}
 			}
+			// 账号槽位/等待计数需要在超时或断开时安全回收
+			accountReleaseFunc = wrapReleaseOnDone(c.Request.Context(), accountReleaseFunc)
+			accountWaitRelease = wrapReleaseOnDone(c.Request.Context(), accountWaitRelease)

 			// 转发请求 - 根据账号平台分流
 			var result *service.ForwardResult
@@ -344,6 +357,9 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 				log.Printf("Bind sticky session failed: %v", err)
 			}
 		}
+		// 账号槽位/等待计数需要在超时或断开时安全回收
+		accountReleaseFunc = wrapReleaseOnDone(c.Request.Context(), accountReleaseFunc)
+		accountWaitRelease = wrapReleaseOnDone(c.Request.Context(), accountWaitRelease)

 		// 转发请求 - 根据账号平台分流
 		var result *service.ForwardResult
@@ -674,7 +690,8 @@ func (h *GatewayHandler) CountTokens(c *gin.Context) {
 	// 校验 billing eligibility（订阅/余额）
 	// 【注意】不计算并发，但需要校验订阅/余额
 	if err := h.billingCacheService.CheckBillingEligibility(c.Request.Context(), apiKey.User, apiKey, apiKey.Group, subscription); err != nil {
-		h.errorResponse(c, http.StatusForbidden, "billing_error", err.Error())
+		status, code, message := billingErrorDetails(err)
+		h.errorResponse(c, status, code, message)
 		return
 	}

@@ -800,3 +817,18 @@ func sendMockWarmupResponse(c *gin.Context, model string) {
 		},
 	})
 }
+
+func billingErrorDetails(err error) (status int, code, message string) {
+	if errors.Is(err, service.ErrBillingServiceUnavailable) {
+		msg := pkgerrors.Message(err)
+		if msg == "" {
+			msg = "Billing service temporarily unavailable. Please retry later."
+		}
+		return http.StatusServiceUnavailable, "billing_service_error", msg
+	}
+	msg := pkgerrors.Message(err)
+	if msg == "" {
+		msg = err.Error()
+	}
+	return http.StatusForbidden, "billing_error", msg
+}
--- a/backend/internal/handler/gateway_helper.go
+++ b/backend/internal/handler/gateway_helper.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"math/rand"
 	"net/http"
+	"sync"
 	"time"

 	"github.com/Wei-Shaw/sub2api/internal/service"
@@ -26,8 +27,8 @@ import (
 const (
 	// maxConcurrencyWait 等待并发槽位的最大时间
 	maxConcurrencyWait = 30 * time.Second
-	// pingInterval 流式响应等待时发送 ping 的间隔
-	pingInterval = 15 * time.Second
+	// defaultPingInterval 流式响应等待时发送 ping 的默认间隔
+	defaultPingInterval = 10 * time.Second
 	// initialBackoff 初始退避时间
 	initialBackoff = 100 * time.Millisecond
 	// backoffMultiplier 退避时间乘数（指数退避）
@@ -44,6 +45,8 @@ const (
 	SSEPingFormatClaude SSEPingFormat = "data: {\"type\": \"ping\"}\n\n"
 	// SSEPingFormatNone indicates no ping should be sent (e.g., OpenAI has no ping spec)
 	SSEPingFormatNone SSEPingFormat = ""
+	// SSEPingFormatComment is an SSE comment ping for OpenAI/Codex CLI clients
+	SSEPingFormatComment SSEPingFormat = ":\n\n"
 )

 // ConcurrencyError represents a concurrency limit error with context
@@ -63,16 +66,38 @@ func (e *ConcurrencyError) Error() string {
 type ConcurrencyHelper struct {
 	concurrencyService *service.ConcurrencyService
 	pingFormat         SSEPingFormat
+	pingInterval       time.Duration
 }

 // NewConcurrencyHelper creates a new ConcurrencyHelper
-func NewConcurrencyHelper(concurrencyService *service.ConcurrencyService, pingFormat SSEPingFormat) *ConcurrencyHelper {
+func NewConcurrencyHelper(concurrencyService *service.ConcurrencyService, pingFormat SSEPingFormat, pingInterval time.Duration) *ConcurrencyHelper {
+	if pingInterval <= 0 {
+		pingInterval = defaultPingInterval
+	}
 	return &ConcurrencyHelper{
 		concurrencyService: concurrencyService,
 		pingFormat:         pingFormat,
+		pingInterval:       pingInterval,
 	}
 }

+// wrapReleaseOnDone ensures release runs at most once and still triggers on context cancellation.
+// 用于避免客户端断开或上游超时导致的并发槽位泄漏。
+func wrapReleaseOnDone(ctx context.Context, releaseFunc func()) func() {
+	if releaseFunc == nil {
+		return nil
+	}
+	var once sync.Once
+	wrapped := func() {
+		once.Do(releaseFunc)
+	}
+	go func() {
+		<-ctx.Done()
+		wrapped()
+	}()
+	return wrapped
+}
+
 // IncrementWaitCount increments the wait count for a user
 func (h *ConcurrencyHelper) IncrementWaitCount(ctx context.Context, userID int64, maxWait int) (bool, error) {
 	return h.concurrencyService.IncrementWaitCount(ctx, userID, maxWait)
@@ -174,7 +199,7 @@ func (h *ConcurrencyHelper) waitForSlotWithPingTimeout(c *gin.Context, slotType
 	// Only create ping ticker if ping is needed
 	var pingCh <-chan time.Time
 	if needPing {
-		pingTicker := time.NewTicker(pingInterval)
+		pingTicker := time.NewTicker(h.pingInterval)
 		defer pingTicker.Stop()
 		pingCh = pingTicker.C
 	}
--- a/backend/internal/handler/gemini_v1beta_handler.go
+++ b/backend/internal/handler/gemini_v1beta_handler.go
@@ -165,7 +165,7 @@ func (h *GatewayHandler) GeminiV1BetaModels(c *gin.Context) {
 	subscription, _ := middleware.GetSubscriptionFromContext(c)

 	// For Gemini native API, do not send Claude-style ping frames.
-	geminiConcurrency := NewConcurrencyHelper(h.concurrencyHelper.concurrencyService, SSEPingFormatNone)
+	geminiConcurrency := NewConcurrencyHelper(h.concurrencyHelper.concurrencyService, SSEPingFormatNone, 0)

 	// 0) wait queue check
 	maxWait := service.CalculateMaxWait(authSubject.Concurrency)
@@ -185,13 +185,16 @@ func (h *GatewayHandler) GeminiV1BetaModels(c *gin.Context) {
 		googleError(c, http.StatusTooManyRequests, err.Error())
 		return
 	}
+	// 确保请求取消时也会释放槽位，避免长连接被动中断造成泄漏
+	userReleaseFunc = wrapReleaseOnDone(c.Request.Context(), userReleaseFunc)
 	if userReleaseFunc != nil {
 		defer userReleaseFunc()
 	}

 	// 2) billing eligibility check (after wait)
 	if err := h.billingCacheService.CheckBillingEligibility(c.Request.Context(), apiKey.User, apiKey, apiKey.Group, subscription); err != nil {
-		googleError(c, http.StatusForbidden, err.Error())
+		status, _, message := billingErrorDetails(err)
+		googleError(c, status, message)
 		return
 	}

@@ -260,6 +263,9 @@ func (h *GatewayHandler) GeminiV1BetaModels(c *gin.Context) {
 				log.Printf("Bind sticky session failed: %v", err)
 			}
 		}
+		// 账号槽位/等待计数需要在超时或断开时安全回收
+		accountReleaseFunc = wrapReleaseOnDone(c.Request.Context(), accountReleaseFunc)
+		accountWaitRelease = wrapReleaseOnDone(c.Request.Context(), accountWaitRelease)

 		// 5) forward (根据平台分流)
 		var result *service.ForwardResult
@@ -373,7 +379,7 @@ func writeUpstreamResponse(c *gin.Context, res *service.UpstreamHTTPResult) {
 	}
 	for k, vv := range res.Headers {
 		// Avoid overriding content-length and hop-by-hop headers.
-		if strings.EqualFold(k, "Content-Length") || strings.EqualFold(k, "Transfer-Encoding") || strings.EqualFold(k, "Connection") {
+		if strings.EqualFold(k, "Content-Length") || strings.EqualFold(k, "Transfer-Encoding") || strings.EqualFold(k, "Connection") || strings.EqualFold(k, "Www-Authenticate") {
 			continue
 		}
 		for _, v := range vv {
--- a/backend/internal/handler/openai_gateway_handler.go
+++ b/backend/internal/handler/openai_gateway_handler.go
@@ -10,6 +10,7 @@ import (
 	"net/http"
 	"time"

+	"github.com/Wei-Shaw/sub2api/internal/config"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/openai"
 	middleware2 "github.com/Wei-Shaw/sub2api/internal/server/middleware"
 	"github.com/Wei-Shaw/sub2api/internal/service"
@@ -29,11 +30,16 @@ func NewOpenAIGatewayHandler(
 	gatewayService *service.OpenAIGatewayService,
 	concurrencyService *service.ConcurrencyService,
 	billingCacheService *service.BillingCacheService,
+	cfg *config.Config,
 ) *OpenAIGatewayHandler {
+	pingInterval := time.Duration(0)
+	if cfg != nil {
+		pingInterval = time.Duration(cfg.Concurrency.PingInterval) * time.Second
+	}
 	return &OpenAIGatewayHandler{
 		gatewayService:      gatewayService,
 		billingCacheService: billingCacheService,
-		concurrencyHelper:   NewConcurrencyHelper(concurrencyService, SSEPingFormatNone),
+		concurrencyHelper:   NewConcurrencyHelper(concurrencyService, SSEPingFormatComment, pingInterval),
 	}
 }

@@ -124,6 +130,8 @@ func (h *OpenAIGatewayHandler) Responses(c *gin.Context) {
 		h.handleConcurrencyError(c, err, "user", streamStarted)
 		return
 	}
+	// 确保请求取消时也会释放槽位，避免长连接被动中断造成泄漏
+	userReleaseFunc = wrapReleaseOnDone(c.Request.Context(), userReleaseFunc)
 	if userReleaseFunc != nil {
 		defer userReleaseFunc()
 	}
@@ -131,7 +139,8 @@ func (h *OpenAIGatewayHandler) Responses(c *gin.Context) {
 	// 2. Re-check billing eligibility after wait
 	if err := h.billingCacheService.CheckBillingEligibility(c.Request.Context(), apiKey.User, apiKey, apiKey.Group, subscription); err != nil {
 		log.Printf("Billing eligibility check failed after wait: %v", err)
-		h.handleStreamingAwareError(c, http.StatusForbidden, "billing_error", err.Error(), streamStarted)
+		status, code, message := billingErrorDetails(err)
+		h.handleStreamingAwareError(c, status, code, message, streamStarted)
 		return
 	}

@@ -201,6 +210,9 @@ func (h *OpenAIGatewayHandler) Responses(c *gin.Context) {
 				log.Printf("Bind sticky session failed: %v", err)
 			}
 		}
+		// 账号槽位/等待计数需要在超时或断开时安全回收
+		accountReleaseFunc = wrapReleaseOnDone(c.Request.Context(), accountReleaseFunc)
+		accountWaitRelease = wrapReleaseOnDone(c.Request.Context(), accountWaitRelease)

 		// Forward request
 		result, err := h.gatewayService.Forward(c.Request.Context(), c, account, body)
--- a/backend/internal/pkg/httpclient/pool.go
+++ b/backend/internal/pkg/httpclient/pool.go
@@ -25,13 +25,14 @@ import (
 	"time"

 	"github.com/Wei-Shaw/sub2api/internal/pkg/proxyutil"
+	"github.com/Wei-Shaw/sub2api/internal/util/urlvalidator"
 )

 // Transport 连接池默认配置
 const (
 	defaultMaxIdleConns        = 100              // 最大空闲连接数
 	defaultMaxIdleConnsPerHost = 10               // 每个主机最大空闲连接数
-	defaultIdleConnTimeout     = 90 * time.Second // 空闲连接超时时间
+	defaultIdleConnTimeout     = 90 * time.Second // 空闲连接超时时间（建议小于上游 LB 超时）
 )

 // Options 定义共享 HTTP 客户端的构建参数
@@ -40,6 +41,9 @@ type Options struct {
 	Timeout               time.Duration // 请求总超时时间
 	ResponseHeaderTimeout time.Duration // 等待响应头超时时间
 	InsecureSkipVerify    bool          // 是否跳过 TLS 证书验证
+	ProxyStrict           bool          // 严格代理模式：代理失败时返回错误而非回退
+	ValidateResolvedIP    bool          // 是否校验解析后的 IP（防止 DNS Rebinding）
+	AllowPrivateHosts     bool          // 允许私有地址解析（与 ValidateResolvedIP 一起使用）

 	// 可选的连接池参数（不设置则使用默认值）
 	MaxIdleConns        int // 最大空闲连接总数（默认 100）
@@ -79,8 +83,12 @@ func buildClient(opts Options) (*http.Client, error) {
 		return nil, err
 	}

+	var rt http.RoundTripper = transport
+	if opts.ValidateResolvedIP && !opts.AllowPrivateHosts {
+		rt = &validatedTransport{base: transport}
+	}
 	return &http.Client{
-		Transport: transport,
+		Transport: rt,
 		Timeout:   opts.Timeout,
 	}, nil
 }
@@ -126,13 +134,32 @@ func buildTransport(opts Options) (*http.Transport, error) {
 }

 func buildClientKey(opts Options) string {
-	return fmt.Sprintf("%s|%s|%s|%t|%d|%d|%d",
+	return fmt.Sprintf("%s|%s|%s|%t|%t|%t|%t|%d|%d|%d",
 		strings.TrimSpace(opts.ProxyURL),
 		opts.Timeout.String(),
 		opts.ResponseHeaderTimeout.String(),
 		opts.InsecureSkipVerify,
+		opts.ProxyStrict,
+		opts.ValidateResolvedIP,
+		opts.AllowPrivateHosts,
 		opts.MaxIdleConns,
 		opts.MaxIdleConnsPerHost,
 		opts.MaxConnsPerHost,
 	)
 }
+
+type validatedTransport struct {
+	base http.RoundTripper
+}
+
+func (t *validatedTransport) RoundTrip(req *http.Request) (*http.Response, error) {
+	if req != nil && req.URL != nil {
+		host := strings.TrimSpace(req.URL.Hostname())
+		if host != "" {
+			if err := urlvalidator.ValidateResolvedIP(host); err != nil {
+				return nil, err
+			}
+		}
+	}
+	return t.base.RoundTrip(req)
+}
--- a/backend/internal/repository/claude_oauth_service.go
+++ b/backend/internal/repository/claude_oauth_service.go
@@ -12,6 +12,7 @@ import (

 	"github.com/Wei-Shaw/sub2api/internal/pkg/oauth"
 	"github.com/Wei-Shaw/sub2api/internal/service"
+	"github.com/Wei-Shaw/sub2api/internal/util/logredact"

 	"github.com/imroc/req/v3"
 )
@@ -54,7 +55,7 @@ func (s *claudeOAuthService) GetOrganizationUUID(ctx context.Context, sessionKey
 		return "", fmt.Errorf("request failed: %w", err)
 	}

-	log.Printf("[OAuth] Step 1 Response - Status: %d, Body: %s", resp.StatusCode, resp.String())
+	log.Printf("[OAuth] Step 1 Response - Status: %d", resp.StatusCode)

 	if !resp.IsSuccessState() {
 		return "", fmt.Errorf("failed to get organizations: status %d, body: %s", resp.StatusCode, resp.String())
@@ -84,8 +85,8 @@ func (s *claudeOAuthService) GetAuthorizationCode(ctx context.Context, sessionKe
 		"code_challenge_method": "S256",
 	}

-	reqBodyJSON, _ := json.Marshal(reqBody)
 	log.Printf("[OAuth] Step 2: Getting authorization code from %s", authURL)
+	reqBodyJSON, _ := json.Marshal(logredact.RedactMap(reqBody))
 	log.Printf("[OAuth] Step 2 Request Body: %s", string(reqBodyJSON))

 	var result struct {
@@ -113,7 +114,7 @@ func (s *claudeOAuthService) GetAuthorizationCode(ctx context.Context, sessionKe
 		return "", fmt.Errorf("request failed: %w", err)
 	}

-	log.Printf("[OAuth] Step 2 Response - Status: %d, Body: %s", resp.StatusCode, resp.String())
+	log.Printf("[OAuth] Step 2 Response - Status: %d, Body: %s", resp.StatusCode, logredact.RedactJSON(resp.Bytes()))

 	if !resp.IsSuccessState() {
 		return "", fmt.Errorf("failed to get authorization code: status %d, body: %s", resp.StatusCode, resp.String())
@@ -141,7 +142,7 @@ func (s *claudeOAuthService) GetAuthorizationCode(ctx context.Context, sessionKe
 		fullCode = authCode + "#" + responseState
 	}

-	log.Printf("[OAuth] Step 2 SUCCESS - Got authorization code: %s...", prefix(authCode, 20))
+	log.Printf("[OAuth] Step 2 SUCCESS - Got authorization code")
 	return fullCode, nil
 }

@@ -173,8 +174,8 @@ func (s *claudeOAuthService) ExchangeCodeForToken(ctx context.Context, code, cod
 		reqBody["expires_in"] = 31536000 // 365 * 24 * 60 * 60 seconds
 	}

-	reqBodyJSON, _ := json.Marshal(reqBody)
 	log.Printf("[OAuth] Step 3: Exchanging code for token at %s", s.tokenURL)
+	reqBodyJSON, _ := json.Marshal(logredact.RedactMap(reqBody))
 	log.Printf("[OAuth] Step 3 Request Body: %s", string(reqBodyJSON))

 	var tokenResp oauth.TokenResponse
@@ -191,7 +192,7 @@ func (s *claudeOAuthService) ExchangeCodeForToken(ctx context.Context, code, cod
 		return nil, fmt.Errorf("request failed: %w", err)
 	}

-	log.Printf("[OAuth] Step 3 Response - Status: %d, Body: %s", resp.StatusCode, resp.String())
+	log.Printf("[OAuth] Step 3 Response - Status: %d, Body: %s", resp.StatusCode, logredact.RedactJSON(resp.Bytes()))

 	if !resp.IsSuccessState() {
 		return nil, fmt.Errorf("token exchange failed: status %d, body: %s", resp.StatusCode, resp.String())
@@ -245,13 +246,3 @@ func createReqClient(proxyURL string) *req.Client {

 	return client
 }
-
-func prefix(s string, n int) string {
-	if n <= 0 {
-		return ""
-	}
-	if len(s) <= n {
-		return s
-	}
-	return s[:n]
-}
--- a/backend/internal/repository/claude_usage_service.go
+++ b/backend/internal/repository/claude_usage_service.go
@@ -15,7 +15,8 @@ import (
 const defaultClaudeUsageURL = "https://api.anthropic.com/api/oauth/usage"

 type claudeUsageService struct {
-	usageURL string
+	usageURL          string
+	allowPrivateHosts bool
 }

 func NewClaudeUsageFetcher() service.ClaudeUsageFetcher {
@@ -24,8 +25,10 @@ func NewClaudeUsageFetcher() service.ClaudeUsageFetcher {

 func (s *claudeUsageService) FetchUsage(ctx context.Context, accessToken, proxyURL string) (*service.ClaudeUsageResponse, error) {
 	client, err := httpclient.GetClient(httpclient.Options{
-		ProxyURL: proxyURL,
-		Timeout:  30 * time.Second,
+		ProxyURL:           proxyURL,
+		Timeout:            30 * time.Second,
+		ValidateResolvedIP: true,
+		AllowPrivateHosts:  s.allowPrivateHosts,
 	})
 	if err != nil {
 		client = &http.Client{Timeout: 30 * time.Second}
--- a/backend/internal/repository/claude_usage_service_test.go
+++ b/backend/internal/repository/claude_usage_service_test.go
@@ -45,7 +45,10 @@ func (s *ClaudeUsageServiceSuite) TestFetchUsage_Success() {
 }`)
 	}))

-	s.fetcher = &claudeUsageService{usageURL: s.srv.URL}
+	s.fetcher = &claudeUsageService{
+		usageURL:          s.srv.URL,
+		allowPrivateHosts: true,
+	}

 	resp, err := s.fetcher.FetchUsage(context.Background(), "at", "://bad-proxy-url")
 	require.NoError(s.T(), err, "FetchUsage")
@@ -64,7 +67,10 @@ func (s *ClaudeUsageServiceSuite) TestFetchUsage_NonOK() {
 		_, _ = io.WriteString(w, "nope")
 	}))

-	s.fetcher = &claudeUsageService{usageURL: s.srv.URL}
+	s.fetcher = &claudeUsageService{
+		usageURL:          s.srv.URL,
+		allowPrivateHosts: true,
+	}

 	_, err := s.fetcher.FetchUsage(context.Background(), "at", "")
 	require.Error(s.T(), err)
@@ -78,7 +84,10 @@ func (s *ClaudeUsageServiceSuite) TestFetchUsage_BadJSON() {
 		_, _ = io.WriteString(w, "not-json")
 	}))

-	s.fetcher = &claudeUsageService{usageURL: s.srv.URL}
+	s.fetcher = &claudeUsageService{
+		usageURL:          s.srv.URL,
+		allowPrivateHosts: true,
+	}

 	_, err := s.fetcher.FetchUsage(context.Background(), "at", "")
 	require.Error(s.T(), err)
@@ -91,7 +100,10 @@ func (s *ClaudeUsageServiceSuite) TestFetchUsage_ContextCancel() {
 		<-r.Context().Done()
 	}))

-	s.fetcher = &claudeUsageService{usageURL: s.srv.URL}
+	s.fetcher = &claudeUsageService{
+		usageURL:          s.srv.URL,
+		allowPrivateHosts: true,
+	}

 	ctx, cancel := context.WithCancel(context.Background())
 	cancel() // Cancel immediately
--- a/backend/internal/repository/github_release_service.go
+++ b/backend/internal/repository/github_release_service.go
@@ -14,18 +14,23 @@ import (
 )

 type githubReleaseClient struct {
-	httpClient *http.Client
+	httpClient        *http.Client
+	allowPrivateHosts bool
 }

 func NewGitHubReleaseClient() service.GitHubReleaseClient {
+	allowPrivate := false
 	sharedClient, err := httpclient.GetClient(httpclient.Options{
-		Timeout: 30 * time.Second,
+		Timeout:            30 * time.Second,
+		ValidateResolvedIP: true,
+		AllowPrivateHosts:  allowPrivate,
 	})
 	if err != nil {
 		sharedClient = &http.Client{Timeout: 30 * time.Second}
 	}
 	return &githubReleaseClient{
-		httpClient: sharedClient,
+		httpClient:        sharedClient,
+		allowPrivateHosts: allowPrivate,
 	}
 }

@@ -64,7 +69,9 @@ func (c *githubReleaseClient) DownloadFile(ctx context.Context, url, dest string
 	}

 	downloadClient, err := httpclient.GetClient(httpclient.Options{
-		Timeout: 10 * time.Minute,
+		Timeout:            10 * time.Minute,
+		ValidateResolvedIP: true,
+		AllowPrivateHosts:  c.allowPrivateHosts,
 	})
 	if err != nil {
 		downloadClient = &http.Client{Timeout: 10 * time.Minute}
--- a/backend/internal/repository/github_release_service_test.go
+++ b/backend/internal/repository/github_release_service_test.go
@@ -37,6 +37,13 @@ func (t *testTransport) RoundTrip(req *http.Request) (*http.Response, error) {
 	return http.DefaultTransport.RoundTrip(newReq)
 }

+func newTestGitHubReleaseClient() *githubReleaseClient {
+	return &githubReleaseClient{
+		httpClient:        &http.Client{},
+		allowPrivateHosts: true,
+	}
+}
+
 func (s *GitHubReleaseServiceSuite) SetupTest() {
 	s.tempDir = s.T().TempDir()
 }
@@ -55,9 +62,7 @@ func (s *GitHubReleaseServiceSuite) TestDownloadFile_EnforcesMaxSize_ContentLeng
 		_, _ = w.Write(bytes.Repeat([]byte("a"), 100))
 	}))

-	client, ok := NewGitHubReleaseClient().(*githubReleaseClient)
-	require.True(s.T(), ok, "type assertion failed")
-	s.client = client
+	s.client = newTestGitHubReleaseClient()

 	dest := filepath.Join(s.tempDir, "file1.bin")
 	err := s.client.DownloadFile(context.Background(), s.srv.URL, dest, 10)
@@ -82,9 +87,7 @@ func (s *GitHubReleaseServiceSuite) TestDownloadFile_EnforcesMaxSize_Chunked() {
 		}
 	}))

-	client, ok := NewGitHubReleaseClient().(*githubReleaseClient)
-	require.True(s.T(), ok, "type assertion failed")
-	s.client = client
+	s.client = newTestGitHubReleaseClient()

 	dest := filepath.Join(s.tempDir, "file2.bin")
 	err := s.client.DownloadFile(context.Background(), s.srv.URL, dest, 10)
@@ -108,9 +111,7 @@ func (s *GitHubReleaseServiceSuite) TestDownloadFile_Success() {
 		}
 	}))

-	client, ok := NewGitHubReleaseClient().(*githubReleaseClient)
-	require.True(s.T(), ok, "type assertion failed")
-	s.client = client
+	s.client = newTestGitHubReleaseClient()

 	dest := filepath.Join(s.tempDir, "file3.bin")
 	err := s.client.DownloadFile(context.Background(), s.srv.URL, dest, 200)
@@ -127,9 +128,7 @@ func (s *GitHubReleaseServiceSuite) TestDownloadFile_404() {
 		w.WriteHeader(http.StatusNotFound)
 	}))

-	client, ok := NewGitHubReleaseClient().(*githubReleaseClient)
-	require.True(s.T(), ok, "type assertion failed")
-	s.client = client
+	s.client = newTestGitHubReleaseClient()

 	dest := filepath.Join(s.tempDir, "notfound.bin")
 	err := s.client.DownloadFile(context.Background(), s.srv.URL, dest, 100)
@@ -145,9 +144,7 @@ func (s *GitHubReleaseServiceSuite) TestFetchChecksumFile_Success() {
 		_, _ = w.Write([]byte("sum"))
 	}))

-	client, ok := NewGitHubReleaseClient().(*githubReleaseClient)
-	require.True(s.T(), ok, "type assertion failed")
-	s.client = client
+	s.client = newTestGitHubReleaseClient()

 	body, err := s.client.FetchChecksumFile(context.Background(), s.srv.URL)
 	require.NoError(s.T(), err, "FetchChecksumFile")
@@ -159,9 +156,7 @@ func (s *GitHubReleaseServiceSuite) TestFetchChecksumFile_Non200() {
 		w.WriteHeader(http.StatusInternalServerError)
 	}))

-	client, ok := NewGitHubReleaseClient().(*githubReleaseClient)
-	require.True(s.T(), ok, "type assertion failed")
-	s.client = client
+	s.client = newTestGitHubReleaseClient()

 	_, err := s.client.FetchChecksumFile(context.Background(), s.srv.URL)
 	require.Error(s.T(), err, "expected error for non-200")
@@ -172,9 +167,7 @@ func (s *GitHubReleaseServiceSuite) TestDownloadFile_ContextCancel() {
 		<-r.Context().Done()
 	}))

-	client, ok := NewGitHubReleaseClient().(*githubReleaseClient)
-	require.True(s.T(), ok, "type assertion failed")
-	s.client = client
+	s.client = newTestGitHubReleaseClient()

 	ctx, cancel := context.WithCancel(context.Background())
 	cancel()
@@ -185,9 +178,7 @@ func (s *GitHubReleaseServiceSuite) TestDownloadFile_ContextCancel() {
 }

 func (s *GitHubReleaseServiceSuite) TestDownloadFile_InvalidURL() {
-	client, ok := NewGitHubReleaseClient().(*githubReleaseClient)
-	require.True(s.T(), ok, "type assertion failed")
-	s.client = client
+	s.client = newTestGitHubReleaseClient()

 	dest := filepath.Join(s.tempDir, "invalid.bin")
 	err := s.client.DownloadFile(context.Background(), "://invalid-url", dest, 100)
@@ -200,9 +191,7 @@ func (s *GitHubReleaseServiceSuite) TestDownloadFile_InvalidDestPath() {
 		_, _ = w.Write([]byte("content"))
 	}))

-	client, ok := NewGitHubReleaseClient().(*githubReleaseClient)
-	require.True(s.T(), ok, "type assertion failed")
-	s.client = client
+	s.client = newTestGitHubReleaseClient()

 	// Use a path that cannot be created (directory doesn't exist)
 	dest := filepath.Join(s.tempDir, "nonexistent", "subdir", "file.bin")
@@ -211,9 +200,7 @@ func (s *GitHubReleaseServiceSuite) TestDownloadFile_InvalidDestPath() {
 }

 func (s *GitHubReleaseServiceSuite) TestFetchChecksumFile_InvalidURL() {
-	client, ok := NewGitHubReleaseClient().(*githubReleaseClient)
-	require.True(s.T(), ok, "type assertion failed")
-	s.client = client
+	s.client = newTestGitHubReleaseClient()

 	_, err := s.client.FetchChecksumFile(context.Background(), "://invalid-url")
 	require.Error(s.T(), err, "expected error for invalid URL")
@@ -247,6 +234,7 @@ func (s *GitHubReleaseServiceSuite) TestFetchLatestRelease_Success() {
 		httpClient: &http.Client{
 			Transport: &testTransport{testServerURL: s.srv.URL},
 		},
+		allowPrivateHosts: true,
 	}

 	release, err := s.client.FetchLatestRelease(context.Background(), "test/repo")
@@ -266,6 +254,7 @@ func (s *GitHubReleaseServiceSuite) TestFetchLatestRelease_Non200() {
 		httpClient: &http.Client{
 			Transport: &testTransport{testServerURL: s.srv.URL},
 		},
+		allowPrivateHosts: true,
 	}

 	_, err := s.client.FetchLatestRelease(context.Background(), "test/repo")
@@ -283,6 +272,7 @@ func (s *GitHubReleaseServiceSuite) TestFetchLatestRelease_InvalidJSON() {
 		httpClient: &http.Client{
 			Transport: &testTransport{testServerURL: s.srv.URL},
 		},
+		allowPrivateHosts: true,
 	}

 	_, err := s.client.FetchLatestRelease(context.Background(), "test/repo")
@@ -298,6 +288,7 @@ func (s *GitHubReleaseServiceSuite) TestFetchLatestRelease_ContextCancel() {
 		httpClient: &http.Client{
 			Transport: &testTransport{testServerURL: s.srv.URL},
 		},
+		allowPrivateHosts: true,
 	}

 	ctx, cancel := context.WithCancel(context.Background())
@@ -312,9 +303,7 @@ func (s *GitHubReleaseServiceSuite) TestFetchChecksumFile_ContextCancel() {
 		<-r.Context().Done()
 	}))

-	client, ok := NewGitHubReleaseClient().(*githubReleaseClient)
-	require.True(s.T(), ok, "type assertion failed")
-	s.client = client
+	s.client = newTestGitHubReleaseClient()

 	ctx, cancel := context.WithCancel(context.Background())
 	cancel()
--- a/backend/internal/repository/http_upstream.go
+++ b/backend/internal/repository/http_upstream.go
@@ -15,6 +15,7 @@ import (
 	"github.com/Wei-Shaw/sub2api/internal/config"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/proxyutil"
 	"github.com/Wei-Shaw/sub2api/internal/service"
+	"github.com/Wei-Shaw/sub2api/internal/util/urlvalidator"
 )

 // 默认配置常量
@@ -30,9 +31,9 @@ const (
 	// defaultMaxConnsPerHost: 默认每主机最大连接数（含活跃连接）
 	// 达到上限后新请求会等待，而非无限创建连接
 	defaultMaxConnsPerHost = 240
-	// defaultIdleConnTimeout: 默认空闲连接超时时间（5分钟）
-	// 超时后连接会被关闭，释放系统资源
-	defaultIdleConnTimeout = 300 * time.Second
+	// defaultIdleConnTimeout: 默认空闲连接超时时间（90秒）
+	// 超时后连接会被关闭，释放系统资源（建议小于上游 LB 超时）
+	defaultIdleConnTimeout = 90 * time.Second
 	// defaultResponseHeaderTimeout: 默认等待响应头超时时间（5分钟）
 	// LLM 请求可能排队较久，需要较长超时
 	defaultResponseHeaderTimeout = 300 * time.Second
@@ -120,6 +121,10 @@ func NewHTTPUpstream(cfg *config.Config) service.HTTPUpstream {
 //   - 调用方必须关闭 resp.Body，否则会导致 inFlight 计数泄漏
 //   - inFlight > 0 的客户端不会被淘汰，确保活跃请求不被中断
 func (s *httpUpstreamService) Do(req *http.Request, proxyURL string, accountID int64, accountConcurrency int) (*http.Response, error) {
+	if err := s.validateRequestHost(req); err != nil {
+		return nil, err
+	}
+
 	// 获取或创建对应的客户端，并标记请求占用
 	entry, err := s.acquireClient(proxyURL, accountID, accountConcurrency)
 	if err != nil {
@@ -145,6 +150,37 @@ func (s *httpUpstreamService) Do(req *http.Request, proxyURL string, accountID i
 	return resp, nil
 }

+func (s *httpUpstreamService) shouldValidateResolvedIP() bool {
+	if s.cfg == nil {
+		return false
+	}
+	return !s.cfg.Security.URLAllowlist.AllowPrivateHosts
+}
+
+func (s *httpUpstreamService) validateRequestHost(req *http.Request) error {
+	if !s.shouldValidateResolvedIP() {
+		return nil
+	}
+	if req == nil || req.URL == nil {
+		return errors.New("request url is nil")
+	}
+	host := strings.TrimSpace(req.URL.Hostname())
+	if host == "" {
+		return errors.New("request host is empty")
+	}
+	if err := urlvalidator.ValidateResolvedIP(host); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (s *httpUpstreamService) redirectChecker(req *http.Request, via []*http.Request) error {
+	if len(via) >= 10 {
+		return errors.New("stopped after 10 redirects")
+	}
+	return s.validateRequestHost(req)
+}
+
 // acquireClient 获取或创建客户端，并标记为进行中请求
 // 用于请求路径，避免在获取后被淘汰
 func (s *httpUpstreamService) acquireClient(proxyURL string, accountID int64, accountConcurrency int) (*upstreamClientEntry, error) {
@@ -232,6 +268,9 @@ func (s *httpUpstreamService) getClientEntry(proxyURL string, accountID int64, a
 		return nil, fmt.Errorf("build transport: %w", err)
 	}
 	client := &http.Client{Transport: transport}
+	if s.shouldValidateResolvedIP() {
+		client.CheckRedirect = s.redirectChecker
+	}
 	entry := &upstreamClientEntry{
 		client:   client,
 		proxyKey: proxyKey,
--- a/backend/internal/repository/http_upstream_test.go
+++ b/backend/internal/repository/http_upstream_test.go
@@ -22,7 +22,13 @@ type HTTPUpstreamSuite struct {
 // SetupTest 每个测试用例执行前的初始化
 // 创建空配置，各测试用例可按需覆盖
 func (s *HTTPUpstreamSuite) SetupTest() {
-	s.cfg = &config.Config{}
+	s.cfg = &config.Config{
+		Security: config.SecurityConfig{
+			URLAllowlist: config.URLAllowlistConfig{
+				AllowPrivateHosts: true,
+			},
+		},
+	}
 }

 // newService 创建测试用的 httpUpstreamService 实例
--- a/backend/internal/repository/pricing_service.go
+++ b/backend/internal/repository/pricing_service.go
@@ -8,6 +8,7 @@ import (
 	"strings"
 	"time"

+	"github.com/Wei-Shaw/sub2api/internal/config"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/httpclient"
 	"github.com/Wei-Shaw/sub2api/internal/service"
 )
@@ -16,9 +17,15 @@ type pricingRemoteClient struct {
 	httpClient *http.Client
 }

-func NewPricingRemoteClient() service.PricingRemoteClient {
+func NewPricingRemoteClient(cfg *config.Config) service.PricingRemoteClient {
+	allowPrivate := false
+	if cfg != nil {
+		allowPrivate = cfg.Security.URLAllowlist.AllowPrivateHosts
+	}
 	sharedClient, err := httpclient.GetClient(httpclient.Options{
-		Timeout: 30 * time.Second,
+		Timeout:            30 * time.Second,
+		ValidateResolvedIP: true,
+		AllowPrivateHosts:  allowPrivate,
 	})
 	if err != nil {
 		sharedClient = &http.Client{Timeout: 30 * time.Second}
--- a/backend/internal/repository/pricing_service_test.go
+++ b/backend/internal/repository/pricing_service_test.go
@@ -6,6 +6,7 @@ import (
 	"net/http/httptest"
 	"testing"

+	"github.com/Wei-Shaw/sub2api/internal/config"
 	"github.com/stretchr/testify/require"
 	"github.com/stretchr/testify/suite"
 )
@@ -19,7 +20,13 @@ type PricingServiceSuite struct {

 func (s *PricingServiceSuite) SetupTest() {
 	s.ctx = context.Background()
-	client, ok := NewPricingRemoteClient().(*pricingRemoteClient)
+	client, ok := NewPricingRemoteClient(&config.Config{
+		Security: config.SecurityConfig{
+			URLAllowlist: config.URLAllowlistConfig{
+				AllowPrivateHosts: true,
+			},
+		},
+	}).(*pricingRemoteClient)
 	require.True(s.T(), ok, "type assertion failed")
 	s.client = client
 }
--- a/backend/internal/repository/proxy_probe_service.go
+++ b/backend/internal/repository/proxy_probe_service.go
@@ -5,28 +5,48 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"log"
 	"net/http"
 	"time"

+	"github.com/Wei-Shaw/sub2api/internal/config"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/httpclient"
 	"github.com/Wei-Shaw/sub2api/internal/service"
 )

-func NewProxyExitInfoProber() service.ProxyExitInfoProber {
-	return &proxyProbeService{ipInfoURL: defaultIPInfoURL}
+func NewProxyExitInfoProber(cfg *config.Config) service.ProxyExitInfoProber {
+	insecure := false
+	allowPrivate := false
+	if cfg != nil {
+		insecure = cfg.Security.ProxyProbe.InsecureSkipVerify
+		allowPrivate = cfg.Security.URLAllowlist.AllowPrivateHosts
+	}
+	if insecure {
+		log.Printf("[ProxyProbe] Warning: TLS verification is disabled for proxy probing.")
+	}
+	return &proxyProbeService{
+		ipInfoURL:          defaultIPInfoURL,
+		insecureSkipVerify: insecure,
+		allowPrivateHosts:  allowPrivate,
+	}
 }

 const defaultIPInfoURL = "https://ipinfo.io/json"

 type proxyProbeService struct {
-	ipInfoURL string
+	ipInfoURL          string
+	insecureSkipVerify bool
+	allowPrivateHosts  bool
 }

 func (s *proxyProbeService) ProbeProxy(ctx context.Context, proxyURL string) (*service.ProxyExitInfo, int64, error) {
 	client, err := httpclient.GetClient(httpclient.Options{
 		ProxyURL:           proxyURL,
 		Timeout:            15 * time.Second,
-		InsecureSkipVerify: true,
+		InsecureSkipVerify: s.insecureSkipVerify,
+		ProxyStrict:        true,
+		ValidateResolvedIP: true,
+		AllowPrivateHosts:  s.allowPrivateHosts,
 	})
 	if err != nil {
 		return nil, 0, fmt.Errorf("failed to create proxy client: %w", err)
--- a/backend/internal/repository/proxy_probe_service_test.go
+++ b/backend/internal/repository/proxy_probe_service_test.go
@@ -20,7 +20,10 @@ type ProxyProbeServiceSuite struct {

 func (s *ProxyProbeServiceSuite) SetupTest() {
 	s.ctx = context.Background()
-	s.prober = &proxyProbeService{ipInfoURL: "http://ipinfo.test/json"}
+	s.prober = &proxyProbeService{
+		ipInfoURL:         "http://ipinfo.test/json",
+		allowPrivateHosts: true,
+	}
 }

 func (s *ProxyProbeServiceSuite) TearDownTest() {
--- a/backend/internal/repository/turnstile_service.go
+++ b/backend/internal/repository/turnstile_service.go
@@ -22,7 +22,8 @@ type turnstileVerifier struct {

 func NewTurnstileVerifier() service.TurnstileVerifier {
 	sharedClient, err := httpclient.GetClient(httpclient.Options{
-		Timeout: 10 * time.Second,
+		Timeout:            10 * time.Second,
+		ValidateResolvedIP: true,
 	})
 	if err != nil {
 		sharedClient = &http.Client{Timeout: 10 * time.Second}
--- a/backend/internal/server/api_contract_test.go
+++ b/backend/internal/server/api_contract_test.go
@@ -294,13 +294,13 @@ func TestAPIContracts(t *testing.T) {
 					"smtp_host": "smtp.example.com",
 					"smtp_port": 587,
 					"smtp_username": "user",
-					"smtp_password": "secret",
+					"smtp_password_configured": true,
 					"smtp_from_email": "no-reply@example.com",
 					"smtp_from_name": "Sub2API",
 					"smtp_use_tls": true,
 					"turnstile_enabled": true,
 					"turnstile_site_key": "site-key",
-					"turnstile_secret_key": "secret-key",
+					"turnstile_secret_key_configured": true,
 					"site_name": "Sub2API",
 					"site_logo": "",
 					"site_subtitle": "Subtitle",
--- a/backend/internal/server/http.go
+++ b/backend/internal/server/http.go
@@ -2,6 +2,7 @@
 package server

 import (
+	"log"
 	"net/http"
 	"time"

@@ -36,6 +37,15 @@ func ProvideRouter(

 	r := gin.New()
 	r.Use(middleware2.Recovery())
+	if len(cfg.Server.TrustedProxies) > 0 {
+		if err := r.SetTrustedProxies(cfg.Server.TrustedProxies); err != nil {
+			log.Printf("Failed to set trusted proxies: %v", err)
+		}
+	} else {
+		if err := r.SetTrustedProxies(nil); err != nil {
+			log.Printf("Failed to disable trusted proxies: %v", err)
+		}
+	}

 	return SetupRouter(r, handlers, jwtAuth, adminAuth, apiKeyAuth, apiKeyService, subscriptionService, cfg)
 }
--- a/backend/internal/server/middleware/api_key_auth.go
+++ b/backend/internal/server/middleware/api_key_auth.go
@@ -19,6 +19,13 @@ func NewAPIKeyAuthMiddleware(apiKeyService *service.APIKeyService, subscriptionS
 // apiKeyAuthWithSubscription API Key认证中间件（支持订阅验证）
 func apiKeyAuthWithSubscription(apiKeyService *service.APIKeyService, subscriptionService *service.SubscriptionService, cfg *config.Config) gin.HandlerFunc {
 	return func(c *gin.Context) {
+		queryKey := strings.TrimSpace(c.Query("key"))
+		queryApiKey := strings.TrimSpace(c.Query("api_key"))
+		if queryKey != "" || queryApiKey != "" {
+			AbortWithError(c, 400, "api_key_in_query_deprecated", "API key in query parameter is deprecated. Please use Authorization header instead.")
+			return
+		}
+
 		// 尝试从Authorization header中提取API key (Bearer scheme)
 		authHeader := c.GetHeader("Authorization")
 		var apiKeyString string
@@ -41,19 +48,9 @@ func apiKeyAuthWithSubscription(apiKeyService *service.APIKeyService, subscripti
 			apiKeyString = c.GetHeader("x-goog-api-key")
 		}

-		// 如果header中没有，尝试从query参数中提取（Google API key风格）
-		if apiKeyString == "" {
-			apiKeyString = c.Query("key")
-		}
-
-		// 兼容常见别名
-		if apiKeyString == "" {
-			apiKeyString = c.Query("api_key")
-		}
-
 		// 如果所有header都没有API key
 		if apiKeyString == "" {
-			AbortWithError(c, 401, "API_KEY_REQUIRED", "API key is required in Authorization header (Bearer scheme), x-api-key header, x-goog-api-key header, or key/api_key query parameter")
+			AbortWithError(c, 401, "API_KEY_REQUIRED", "API key is required in Authorization header (Bearer scheme), x-api-key header, or x-goog-api-key header")
 			return
 		}

--- a/backend/internal/server/middleware/api_key_auth_google.go
+++ b/backend/internal/server/middleware/api_key_auth_google.go
@@ -22,6 +22,10 @@ func APIKeyAuthGoogle(apiKeyService *service.APIKeyService, cfg *config.Config)
 // It is intended for Gemini native endpoints (/v1beta) to match Gemini SDK expectations.
 func APIKeyAuthWithSubscriptionGoogle(apiKeyService *service.APIKeyService, subscriptionService *service.SubscriptionService, cfg *config.Config) gin.HandlerFunc {
 	return func(c *gin.Context) {
+		if v := strings.TrimSpace(c.Query("api_key")); v != "" {
+			abortWithGoogleError(c, 400, "Query parameter api_key is deprecated. Use Authorization header or key instead.")
+			return
+		}
 		apiKeyString := extractAPIKeyFromRequest(c)
 		if apiKeyString == "" {
 			abortWithGoogleError(c, 401, "API key is required")
@@ -116,15 +120,18 @@ func extractAPIKeyFromRequest(c *gin.Context) string {
 	if v := strings.TrimSpace(c.GetHeader("x-goog-api-key")); v != "" {
 		return v
 	}
-	if v := strings.TrimSpace(c.Query("key")); v != "" {
-		return v
-	}
-	if v := strings.TrimSpace(c.Query("api_key")); v != "" {
-		return v
+	if allowGoogleQueryKey(c.Request.URL.Path) {
+		if v := strings.TrimSpace(c.Query("key")); v != "" {
+			return v
+		}
 	}
 	return ""
 }

+func allowGoogleQueryKey(path string) bool {
+	return strings.HasPrefix(path, "/v1beta") || strings.HasPrefix(path, "/antigravity/v1beta")
+}
+
 func abortWithGoogleError(c *gin.Context, status int, message string) {
 	c.JSON(status, gin.H{
 		"error": gin.H{
--- a/backend/internal/server/middleware/api_key_auth_google_test.go
+++ b/backend/internal/server/middleware/api_key_auth_google_test.go
@@ -109,6 +109,58 @@ func TestApiKeyAuthWithSubscriptionGoogle_MissingKey(t *testing.T) {
 	require.Equal(t, "UNAUTHENTICATED", resp.Error.Status)
 }

+func TestApiKeyAuthWithSubscriptionGoogle_QueryApiKeyRejected(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	r := gin.New()
+	apiKeyService := newTestAPIKeyService(fakeAPIKeyRepo{
+		getByKey: func(ctx context.Context, key string) (*service.APIKey, error) {
+			return nil, errors.New("should not be called")
+		},
+	})
+	r.Use(APIKeyAuthWithSubscriptionGoogle(apiKeyService, nil, &config.Config{}))
+	r.GET("/v1beta/test", func(c *gin.Context) { c.JSON(200, gin.H{"ok": true}) })
+
+	req := httptest.NewRequest(http.MethodGet, "/v1beta/test?api_key=legacy", nil)
+	rec := httptest.NewRecorder()
+	r.ServeHTTP(rec, req)
+
+	require.Equal(t, http.StatusBadRequest, rec.Code)
+	var resp googleErrorResponse
+	require.NoError(t, json.Unmarshal(rec.Body.Bytes(), &resp))
+	require.Equal(t, http.StatusBadRequest, resp.Error.Code)
+	require.Equal(t, "Query parameter api_key is deprecated. Use Authorization header or key instead.", resp.Error.Message)
+	require.Equal(t, "INVALID_ARGUMENT", resp.Error.Status)
+}
+
+func TestApiKeyAuthWithSubscriptionGoogle_QueryKeyAllowedOnV1Beta(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	r := gin.New()
+	apiKeyService := newTestAPIKeyService(fakeAPIKeyRepo{
+		getByKey: func(ctx context.Context, key string) (*service.APIKey, error) {
+			return &service.APIKey{
+				ID:     1,
+				Key:    key,
+				Status: service.StatusActive,
+				User: &service.User{
+					ID:     123,
+					Status: service.StatusActive,
+				},
+			}, nil
+		},
+	})
+	cfg := &config.Config{RunMode: config.RunModeSimple}
+	r.Use(APIKeyAuthWithSubscriptionGoogle(apiKeyService, nil, cfg))
+	r.GET("/v1beta/test", func(c *gin.Context) { c.JSON(200, gin.H{"ok": true}) })
+
+	req := httptest.NewRequest(http.MethodGet, "/v1beta/test?key=valid", nil)
+	rec := httptest.NewRecorder()
+	r.ServeHTTP(rec, req)
+
+	require.Equal(t, http.StatusOK, rec.Code)
+}
+
 func TestApiKeyAuthWithSubscriptionGoogle_InvalidKey(t *testing.T) {
 	gin.SetMode(gin.TestMode)

--- a/backend/internal/server/middleware/cors.go
+++ b/backend/internal/server/middleware/cors.go
@@ -1,24 +1,103 @@
 package middleware

 import (
+	"log"
+	"net/http"
+	"strings"
+	"sync"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
 	"github.com/gin-gonic/gin"
 )

+var corsWarningOnce sync.Once
+
 // CORS 跨域中间件
-func CORS() gin.HandlerFunc {
+func CORS(cfg config.CORSConfig) gin.HandlerFunc {
+	allowedOrigins := normalizeOrigins(cfg.AllowedOrigins)
+	allowAll := false
+	for _, origin := range allowedOrigins {
+		if origin == "*" {
+			allowAll = true
+			break
+		}
+	}
+	wildcardWithSpecific := allowAll && len(allowedOrigins) > 1
+	if wildcardWithSpecific {
+		allowedOrigins = []string{"*"}
+	}
+	allowCredentials := cfg.AllowCredentials
+
+	corsWarningOnce.Do(func() {
+		if len(allowedOrigins) == 0 {
+			log.Println("Warning: CORS allowed_origins not configured; cross-origin requests will be rejected.")
+		}
+		if wildcardWithSpecific {
+			log.Println("Warning: CORS allowed_origins includes '*'; wildcard will take precedence over explicit origins.")
+		}
+		if allowAll && allowCredentials {
+			log.Println("Warning: CORS allowed_origins set to '*', disabling allow_credentials.")
+		}
+	})
+	if allowAll && allowCredentials {
+		allowCredentials = false
+	}
+
+	allowedSet := make(map[string]struct{}, len(allowedOrigins))
+	for _, origin := range allowedOrigins {
+		if origin == "" || origin == "*" {
+			continue
+		}
+		allowedSet[origin] = struct{}{}
+	}
+
 	return func(c *gin.Context) {
-		// 设置允许跨域的响应头
-		c.Writer.Header().Set("Access-Control-Allow-Origin", "*")
-		c.Writer.Header().Set("Access-Control-Allow-Credentials", "true")
+		origin := strings.TrimSpace(c.GetHeader("Origin"))
+		originAllowed := allowAll
+		if origin != "" && !allowAll {
+			_, originAllowed = allowedSet[origin]
+		}
+
+		if originAllowed {
+			if allowAll {
+				c.Writer.Header().Set("Access-Control-Allow-Origin", "*")
+			} else if origin != "" {
+				c.Writer.Header().Set("Access-Control-Allow-Origin", origin)
+				c.Writer.Header().Add("Vary", "Origin")
+			}
+			if allowCredentials {
+				c.Writer.Header().Set("Access-Control-Allow-Credentials", "true")
+			}
+		}
+
 		c.Writer.Header().Set("Access-Control-Allow-Headers", "Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization, accept, origin, Cache-Control, X-Requested-With, X-API-Key")
 		c.Writer.Header().Set("Access-Control-Allow-Methods", "POST, OPTIONS, GET, PUT, DELETE, PATCH")

 		// 处理预检请求
-		if c.Request.Method == "OPTIONS" {
-			c.AbortWithStatus(204)
+		if c.Request.Method == http.MethodOptions {
+			if originAllowed {
+				c.AbortWithStatus(http.StatusNoContent)
+			} else {
+				c.AbortWithStatus(http.StatusForbidden)
+			}
 			return
 		}

 		c.Next()
 	}
 }
+
+func normalizeOrigins(values []string) []string {
+	if len(values) == 0 {
+		return nil
+	}
+	normalized := make([]string, 0, len(values))
+	for _, value := range values {
+		trimmed := strings.TrimSpace(value)
+		if trimmed == "" {
+			continue
+		}
+		normalized = append(normalized, trimmed)
+	}
+	return normalized
+}
--- a/backend/internal/server/middleware/security_headers.go
+++ b/backend/internal/server/middleware/security_headers.go
@@ -0,0 +1,26 @@
+package middleware
+
+import (
+	"strings"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/gin-gonic/gin"
+)
+
+// SecurityHeaders sets baseline security headers for all responses.
+func SecurityHeaders(cfg config.CSPConfig) gin.HandlerFunc {
+	policy := strings.TrimSpace(cfg.Policy)
+	if policy == "" {
+		policy = config.DefaultCSPPolicy
+	}
+
+	return func(c *gin.Context) {
+		c.Header("X-Content-Type-Options", "nosniff")
+		c.Header("X-Frame-Options", "DENY")
+		c.Header("Referrer-Policy", "strict-origin-when-cross-origin")
+		if cfg.Enabled {
+			c.Header("Content-Security-Policy", policy)
+		}
+		c.Next()
+	}
+}
--- a/backend/internal/server/router.go
+++ b/backend/internal/server/router.go
@@ -24,7 +24,8 @@ func SetupRouter(
 ) *gin.Engine {
 	// 应用中间件
 	r.Use(middleware2.Logger())
-	r.Use(middleware2.CORS())
+	r.Use(middleware2.CORS(cfg.CORS))
+	r.Use(middleware2.SecurityHeaders(cfg.Security.CSP))

 	// Serve embedded frontend if available
 	if web.HasEmbeddedFrontend() {
--- a/backend/internal/service/account_test_service.go
+++ b/backend/internal/service/account_test_service.go
@@ -7,6 +7,7 @@ import (
 	"crypto/rand"
 	"encoding/hex"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"log"
@@ -14,9 +15,11 @@ import (
 	"regexp"
 	"strings"

+	"github.com/Wei-Shaw/sub2api/internal/config"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/claude"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/geminicli"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/openai"
+	"github.com/Wei-Shaw/sub2api/internal/util/urlvalidator"
 	"github.com/gin-gonic/gin"
 	"github.com/google/uuid"
 )
@@ -45,6 +48,7 @@ type AccountTestService struct {
 	geminiTokenProvider       *GeminiTokenProvider
 	antigravityGatewayService *AntigravityGatewayService
 	httpUpstream              HTTPUpstream
+	cfg                       *config.Config
 }

 // NewAccountTestService creates a new AccountTestService
@@ -53,15 +57,32 @@ func NewAccountTestService(
 	geminiTokenProvider *GeminiTokenProvider,
 	antigravityGatewayService *AntigravityGatewayService,
 	httpUpstream HTTPUpstream,
+	cfg *config.Config,
 ) *AccountTestService {
 	return &AccountTestService{
 		accountRepo:               accountRepo,
 		geminiTokenProvider:       geminiTokenProvider,
 		antigravityGatewayService: antigravityGatewayService,
 		httpUpstream:              httpUpstream,
+		cfg:                       cfg,
 	}
 }

+func (s *AccountTestService) validateUpstreamBaseURL(raw string) (string, error) {
+	if s.cfg == nil {
+		return "", errors.New("config is not available")
+	}
+	normalized, err := urlvalidator.ValidateHTTPSURL(raw, urlvalidator.ValidationOptions{
+		AllowedHosts:     s.cfg.Security.URLAllowlist.UpstreamHosts,
+		RequireAllowlist: true,
+		AllowPrivate:     s.cfg.Security.URLAllowlist.AllowPrivateHosts,
+	})
+	if err != nil {
+		return "", err
+	}
+	return normalized, nil
+}
+
 // generateSessionString generates a Claude Code style session string
 func generateSessionString() (string, error) {
 	bytes := make([]byte, 32)
@@ -183,11 +204,15 @@ func (s *AccountTestService) testClaudeAccountConnection(c *gin.Context, account
 			return s.sendErrorAndEnd(c, "No API key available")
 		}

-		apiURL = account.GetBaseURL()
-		if apiURL == "" {
-			apiURL = "https://api.anthropic.com"
+		baseURL := account.GetBaseURL()
+		if baseURL == "" {
+			baseURL = "https://api.anthropic.com"
 		}
-		apiURL = strings.TrimSuffix(apiURL, "/") + "/v1/messages"
+		normalizedBaseURL, err := s.validateUpstreamBaseURL(baseURL)
+		if err != nil {
+			return s.sendErrorAndEnd(c, fmt.Sprintf("Invalid base URL: %s", err.Error()))
+		}
+		apiURL = strings.TrimSuffix(normalizedBaseURL, "/") + "/v1/messages"
 	} else {
 		return s.sendErrorAndEnd(c, fmt.Sprintf("Unsupported account type: %s", account.Type))
 	}
@@ -300,7 +325,11 @@ func (s *AccountTestService) testOpenAIAccountConnection(c *gin.Context, account
 		if baseURL == "" {
 			baseURL = "https://api.openai.com"
 		}
-		apiURL = strings.TrimSuffix(baseURL, "/") + "/responses"
+		normalizedBaseURL, err := s.validateUpstreamBaseURL(baseURL)
+		if err != nil {
+			return s.sendErrorAndEnd(c, fmt.Sprintf("Invalid base URL: %s", err.Error()))
+		}
+		apiURL = strings.TrimSuffix(normalizedBaseURL, "/") + "/responses"
 	} else {
 		return s.sendErrorAndEnd(c, fmt.Sprintf("Unsupported account type: %s", account.Type))
 	}
@@ -480,10 +509,14 @@ func (s *AccountTestService) buildGeminiAPIKeyRequest(ctx context.Context, accou
 	if baseURL == "" {
 		baseURL = geminicli.AIStudioBaseURL
 	}
+	normalizedBaseURL, err := s.validateUpstreamBaseURL(baseURL)
+	if err != nil {
+		return nil, err
+	}

 	// Use streamGenerateContent for real-time feedback
 	fullURL := fmt.Sprintf("%s/v1beta/models/%s:streamGenerateContent?alt=sse",
-		strings.TrimRight(baseURL, "/"), modelID)
+		strings.TrimRight(normalizedBaseURL, "/"), modelID)

 	req, err := http.NewRequestWithContext(ctx, "POST", fullURL, bytes.NewReader(payload))
 	if err != nil {
@@ -515,7 +548,11 @@ func (s *AccountTestService) buildGeminiOAuthRequest(ctx context.Context, accoun
 		if strings.TrimSpace(baseURL) == "" {
 			baseURL = geminicli.AIStudioBaseURL
 		}
-		fullURL := fmt.Sprintf("%s/v1beta/models/%s:streamGenerateContent?alt=sse", strings.TrimRight(baseURL, "/"), modelID)
+		normalizedBaseURL, err := s.validateUpstreamBaseURL(baseURL)
+		if err != nil {
+			return nil, err
+		}
+		fullURL := fmt.Sprintf("%s/v1beta/models/%s:streamGenerateContent?alt=sse", strings.TrimRight(normalizedBaseURL, "/"), modelID)

 		req, err := http.NewRequestWithContext(ctx, http.MethodPost, fullURL, bytes.NewReader(payload))
 		if err != nil {
@@ -544,7 +581,11 @@ func (s *AccountTestService) buildCodeAssistRequest(ctx context.Context, accessT
 	}
 	wrappedBytes, _ := json.Marshal(wrapped)

-	fullURL := fmt.Sprintf("%s/v1internal:streamGenerateContent?alt=sse", geminicli.GeminiCliBaseURL)
+	normalizedBaseURL, err := s.validateUpstreamBaseURL(geminicli.GeminiCliBaseURL)
+	if err != nil {
+		return nil, err
+	}
+	fullURL := fmt.Sprintf("%s/v1internal:streamGenerateContent?alt=sse", normalizedBaseURL)

 	req, err := http.NewRequestWithContext(ctx, "POST", fullURL, bytes.NewReader(wrappedBytes))
 	if err != nil {
--- a/backend/internal/service/antigravity_gateway_service.go
+++ b/backend/internal/service/antigravity_gateway_service.go
@@ -11,6 +11,7 @@ import (
 	"log"
 	"net/http"
 	"strings"
+	"sync/atomic"
 	"time"

 	"github.com/Wei-Shaw/sub2api/internal/pkg/antigravity"
@@ -916,57 +917,145 @@ func (s *AntigravityGatewayService) handleGeminiStreamingResponse(c *gin.Context
 		return nil, errors.New("streaming not supported")
 	}

-	reader := bufio.NewReader(resp.Body)
+	// 使用 Scanner 并限制单行大小，避免 ReadString 无上限导致 OOM
+	scanner := bufio.NewScanner(resp.Body)
+	maxLineSize := defaultMaxLineSize
+	if s.settingService.cfg != nil && s.settingService.cfg.Gateway.MaxLineSize > 0 {
+		maxLineSize = s.settingService.cfg.Gateway.MaxLineSize
+	}
+	scanner.Buffer(make([]byte, 64*1024), maxLineSize)
 	usage := &ClaudeUsage{}
 	var firstTokenMs *int

+	type scanEvent struct {
+		line string
+		err  error
+	}
+	// 独立 goroutine 读取上游，避免读取阻塞影响超时处理
+	events := make(chan scanEvent, 16)
+	done := make(chan struct{})
+	sendEvent := func(ev scanEvent) bool {
+		select {
+		case events <- ev:
+			return true
+		case <-done:
+			return false
+		}
+	}
+	var lastReadAt int64
+	atomic.StoreInt64(&lastReadAt, time.Now().UnixNano())
+	go func() {
+		defer close(events)
+		for scanner.Scan() {
+			atomic.StoreInt64(&lastReadAt, time.Now().UnixNano())
+			if !sendEvent(scanEvent{line: scanner.Text()}) {
+				return
+			}
+		}
+		if err := scanner.Err(); err != nil {
+			_ = sendEvent(scanEvent{err: err})
+		}
+	}()
+	defer close(done)
+
+	// 上游数据间隔超时保护（防止上游挂起长期占用连接）
+	streamInterval := time.Duration(0)
+	if s.settingService.cfg != nil && s.settingService.cfg.Gateway.StreamDataIntervalTimeout > 0 {
+		streamInterval = time.Duration(s.settingService.cfg.Gateway.StreamDataIntervalTimeout) * time.Second
+	}
+	var intervalTicker *time.Ticker
+	if streamInterval > 0 {
+		intervalTicker = time.NewTicker(streamInterval)
+		defer intervalTicker.Stop()
+	}
+	var intervalCh <-chan time.Time
+	if intervalTicker != nil {
+		intervalCh = intervalTicker.C
+	}
+
+	// 仅发送一次错误事件，避免多次写入导致协议混乱
+	errorEventSent := false
+	sendErrorEvent := func(reason string) {
+		if errorEventSent {
+			return
+		}
+		errorEventSent = true
+		_, _ = fmt.Fprintf(c.Writer, "event: error\ndata: {\"error\":\"%s\"}\n\n", reason)
+		flusher.Flush()
+	}
+
 	for {
-		line, err := reader.ReadString('\n')
-		if len(line) > 0 {
+		select {
+		case ev, ok := <-events:
+			if !ok {
+				return &antigravityStreamResult{usage: usage, firstTokenMs: firstTokenMs}, nil
+			}
+			if ev.err != nil {
+				if errors.Is(ev.err, bufio.ErrTooLong) {
+					log.Printf("SSE line too long (antigravity): max_size=%d error=%v", maxLineSize, ev.err)
+					sendErrorEvent("response_too_large")
+					return &antigravityStreamResult{usage: usage, firstTokenMs: firstTokenMs}, ev.err
+				}
+				sendErrorEvent("stream_read_error")
+				return nil, ev.err
+			}
+
+			line := ev.line
 			trimmed := strings.TrimRight(line, "\r\n")
 			if strings.HasPrefix(trimmed, "data:") {
 				payload := strings.TrimSpace(strings.TrimPrefix(trimmed, "data:"))
 				if payload == "" || payload == "[DONE]" {
-					_, _ = io.WriteString(c.Writer, line)
-					flusher.Flush()
-				} else {
-					// 解包 v1internal 响应
-					inner, parseErr := s.unwrapV1InternalResponse([]byte(payload))
-					if parseErr == nil && inner != nil {
-						payload = string(inner)
-					}
-
-					// 解析 usage
-					var parsed map[string]any
-					if json.Unmarshal(inner, &parsed) == nil {
-						if u := extractGeminiUsage(parsed); u != nil {
-							usage = u
-						}
-					}
-
-					if firstTokenMs == nil {
-						ms := int(time.Since(startTime).Milliseconds())
-						firstTokenMs = &ms
-					}
-
-					_, _ = fmt.Fprintf(c.Writer, "data: %s\n\n", payload)
+					if _, err := fmt.Fprintf(c.Writer, "%s\n", line); err != nil {
+						sendErrorEvent("write_failed")
+						return &antigravityStreamResult{usage: usage, firstTokenMs: firstTokenMs}, err
+					}
 					flusher.Flush()
+					continue
 				}
-			} else {
-				_, _ = io.WriteString(c.Writer, line)
-				flusher.Flush()
-			}
-		}

-		if errors.Is(err, io.EOF) {
-			break
-		}
-		if err != nil {
-			return nil, err
+				// 解包 v1internal 响应
+				inner, parseErr := s.unwrapV1InternalResponse([]byte(payload))
+				if parseErr == nil && inner != nil {
+					payload = string(inner)
+				}
+
+				// 解析 usage
+				var parsed map[string]any
+				if json.Unmarshal(inner, &parsed) == nil {
+					if u := extractGeminiUsage(parsed); u != nil {
+						usage = u
+					}
+				}
+
+				if firstTokenMs == nil {
+					ms := int(time.Since(startTime).Milliseconds())
+					firstTokenMs = &ms
+				}
+
+				if _, err := fmt.Fprintf(c.Writer, "data: %s\n\n", payload); err != nil {
+					sendErrorEvent("write_failed")
+					return &antigravityStreamResult{usage: usage, firstTokenMs: firstTokenMs}, err
+				}
+				flusher.Flush()
+				continue
+			}
+
+			if _, err := fmt.Fprintf(c.Writer, "%s\n", line); err != nil {
+				sendErrorEvent("write_failed")
+				return &antigravityStreamResult{usage: usage, firstTokenMs: firstTokenMs}, err
+			}
+			flusher.Flush()
+
+		case <-intervalCh:
+			lastRead := time.Unix(0, atomic.LoadInt64(&lastReadAt))
+			if time.Since(lastRead) < streamInterval {
+				continue
+			}
+			log.Printf("Stream data interval timeout (antigravity)")
+			sendErrorEvent("stream_timeout")
+			return &antigravityStreamResult{usage: usage, firstTokenMs: firstTokenMs}, fmt.Errorf("stream data interval timeout")
 		}
 	}
-
-	return &antigravityStreamResult{usage: usage, firstTokenMs: firstTokenMs}, nil
 }

 func (s *AntigravityGatewayService) handleGeminiNonStreamingResponse(c *gin.Context, resp *http.Response) (*ClaudeUsage, error) {
@@ -1105,7 +1194,13 @@ func (s *AntigravityGatewayService) handleClaudeStreamingResponse(c *gin.Context

 	processor := antigravity.NewStreamingProcessor(originalModel)
 	var firstTokenMs *int
-	reader := bufio.NewReader(resp.Body)
+	// 使用 Scanner 并限制单行大小，避免 ReadString 无上限导致 OOM
+	scanner := bufio.NewScanner(resp.Body)
+	maxLineSize := defaultMaxLineSize
+	if s.settingService.cfg != nil && s.settingService.cfg.Gateway.MaxLineSize > 0 {
+		maxLineSize = s.settingService.cfg.Gateway.MaxLineSize
+	}
+	scanner.Buffer(make([]byte, 64*1024), maxLineSize)

 	// 辅助函数：转换 antigravity.ClaudeUsage 到 service.ClaudeUsage
 	convertUsage := func(agUsage *antigravity.ClaudeUsage) *ClaudeUsage {
@@ -1120,13 +1215,85 @@ func (s *AntigravityGatewayService) handleClaudeStreamingResponse(c *gin.Context
 		}
 	}

-	for {
-		line, err := reader.ReadString('\n')
-		if err != nil && !errors.Is(err, io.EOF) {
-			return nil, fmt.Errorf("stream read error: %w", err)
+	type scanEvent struct {
+		line string
+		err  error
+	}
+	// 独立 goroutine 读取上游，避免读取阻塞影响超时处理
+	events := make(chan scanEvent, 16)
+	done := make(chan struct{})
+	sendEvent := func(ev scanEvent) bool {
+		select {
+		case events <- ev:
+			return true
+		case <-done:
+			return false
 		}
+	}
+	var lastReadAt int64
+	atomic.StoreInt64(&lastReadAt, time.Now().UnixNano())
+	go func() {
+		defer close(events)
+		for scanner.Scan() {
+			atomic.StoreInt64(&lastReadAt, time.Now().UnixNano())
+			if !sendEvent(scanEvent{line: scanner.Text()}) {
+				return
+			}
+		}
+		if err := scanner.Err(); err != nil {
+			_ = sendEvent(scanEvent{err: err})
+		}
+	}()
+	defer close(done)

-		if len(line) > 0 {
+	streamInterval := time.Duration(0)
+	if s.settingService.cfg != nil && s.settingService.cfg.Gateway.StreamDataIntervalTimeout > 0 {
+		streamInterval = time.Duration(s.settingService.cfg.Gateway.StreamDataIntervalTimeout) * time.Second
+	}
+	var intervalTicker *time.Ticker
+	if streamInterval > 0 {
+		intervalTicker = time.NewTicker(streamInterval)
+		defer intervalTicker.Stop()
+	}
+	var intervalCh <-chan time.Time
+	if intervalTicker != nil {
+		intervalCh = intervalTicker.C
+	}
+
+	// 仅发送一次错误事件，避免多次写入导致协议混乱
+	errorEventSent := false
+	sendErrorEvent := func(reason string) {
+		if errorEventSent {
+			return
+		}
+		errorEventSent = true
+		_, _ = fmt.Fprintf(c.Writer, "event: error\ndata: {\"error\":\"%s\"}\n\n", reason)
+		flusher.Flush()
+	}
+
+	for {
+		select {
+		case ev, ok := <-events:
+			if !ok {
+				// 发送结束事件
+				finalEvents, agUsage := processor.Finish()
+				if len(finalEvents) > 0 {
+					_, _ = c.Writer.Write(finalEvents)
+					flusher.Flush()
+				}
+				return &antigravityStreamResult{usage: convertUsage(agUsage), firstTokenMs: firstTokenMs}, nil
+			}
+			if ev.err != nil {
+				if errors.Is(ev.err, bufio.ErrTooLong) {
+					log.Printf("SSE line too long (antigravity): max_size=%d error=%v", maxLineSize, ev.err)
+					sendErrorEvent("response_too_large")
+					return &antigravityStreamResult{usage: convertUsage(nil), firstTokenMs: firstTokenMs}, ev.err
+				}
+				sendErrorEvent("stream_read_error")
+				return nil, fmt.Errorf("stream read error: %w", ev.err)
+			}
+
+			line := ev.line
 			// 处理 SSE 行，转换为 Claude 格式
 			claudeEvents := processor.ProcessLine(strings.TrimRight(line, "\r\n"))

@@ -1141,23 +1308,21 @@ func (s *AntigravityGatewayService) handleClaudeStreamingResponse(c *gin.Context
 					if len(finalEvents) > 0 {
 						_, _ = c.Writer.Write(finalEvents)
 					}
+					sendErrorEvent("write_failed")
 					return &antigravityStreamResult{usage: convertUsage(agUsage), firstTokenMs: firstTokenMs}, writeErr
 				}
 				flusher.Flush()
 			}
-		}

-		if errors.Is(err, io.EOF) {
-			break
+		case <-intervalCh:
+			lastRead := time.Unix(0, atomic.LoadInt64(&lastReadAt))
+			if time.Since(lastRead) < streamInterval {
+				continue
+			}
+			log.Printf("Stream data interval timeout (antigravity)")
+			sendErrorEvent("stream_timeout")
+			return &antigravityStreamResult{usage: convertUsage(nil), firstTokenMs: firstTokenMs}, fmt.Errorf("stream data interval timeout")
 		}
 	}

-	// 发送结束事件
-	finalEvents, agUsage := processor.Finish()
-	if len(finalEvents) > 0 {
-		_, _ = c.Writer.Write(finalEvents)
-		flusher.Flush()
-	}
-
-	return &antigravityStreamResult{usage: convertUsage(agUsage), firstTokenMs: firstTokenMs}, nil
 }
--- a/backend/internal/service/auth_service.go
+++ b/backend/internal/service/auth_service.go
@@ -221,9 +221,33 @@ func (s *AuthService) SendVerifyCodeAsync(ctx context.Context, email string) (*S

 // VerifyTurnstile 验证Turnstile token
 func (s *AuthService) VerifyTurnstile(ctx context.Context, token string, remoteIP string) error {
+	required := s.cfg != nil && s.cfg.Server.Mode == "release" && s.cfg.Turnstile.Required
+
+	if required {
+		if s.settingService == nil {
+			log.Println("[Auth] Turnstile required but settings service is not configured")
+			return ErrTurnstileNotConfigured
+		}
+		enabled := s.settingService.IsTurnstileEnabled(ctx)
+		secretConfigured := s.settingService.GetTurnstileSecretKey(ctx) != ""
+		if !enabled || !secretConfigured {
+			log.Printf("[Auth] Turnstile required but not configured (enabled=%v, secret_configured=%v)", enabled, secretConfigured)
+			return ErrTurnstileNotConfigured
+		}
+	}
+
 	if s.turnstileService == nil {
+		if required {
+			log.Println("[Auth] Turnstile required but service not configured")
+			return ErrTurnstileNotConfigured
+		}
 		return nil // 服务未配置则跳过验证
 	}
+
+	if !required && s.settingService != nil && s.settingService.IsTurnstileEnabled(ctx) && s.settingService.GetTurnstileSecretKey(ctx) == "" {
+		log.Println("[Auth] Turnstile enabled but secret key not configured")
+	}
+
 	return s.turnstileService.VerifyToken(ctx, token, remoteIP)
 }

--- a/backend/internal/service/billing_cache_service.go
+++ b/backend/internal/service/billing_cache_service.go
@@ -16,7 +16,8 @@ import (
 // 注：ErrInsufficientBalance在redeem_service.go中定义
 // 注：ErrDailyLimitExceeded/ErrWeeklyLimitExceeded/ErrMonthlyLimitExceeded在subscription_service.go中定义
 var (
-	ErrSubscriptionInvalid = infraerrors.Forbidden("SUBSCRIPTION_INVALID", "subscription is invalid or expired")
+	ErrSubscriptionInvalid       = infraerrors.Forbidden("SUBSCRIPTION_INVALID", "subscription is invalid or expired")
+	ErrBillingServiceUnavailable = infraerrors.ServiceUnavailable("BILLING_SERVICE_ERROR", "Billing service temporarily unavailable. Please retry later.")
 )

 // subscriptionCacheData 订阅缓存数据结构（内部使用）
@@ -72,10 +73,11 @@ type cacheWriteTask struct {
 // BillingCacheService 计费缓存服务
 // 负责余额和订阅数据的缓存管理，提供高性能的计费资格检查
 type BillingCacheService struct {
-	cache    BillingCache
-	userRepo UserRepository
-	subRepo  UserSubscriptionRepository
-	cfg      *config.Config
+	cache          BillingCache
+	userRepo       UserRepository
+	subRepo        UserSubscriptionRepository
+	cfg            *config.Config
+	circuitBreaker *billingCircuitBreaker

 	cacheWriteChan     chan cacheWriteTask
 	cacheWriteWg       sync.WaitGroup
@@ -95,6 +97,7 @@ func NewBillingCacheService(cache BillingCache, userRepo UserRepository, subRepo
 		subRepo:  subRepo,
 		cfg:      cfg,
 	}
+	svc.circuitBreaker = newBillingCircuitBreaker(cfg.Billing.CircuitBreaker)
 	svc.startCacheWriteWorkers()
 	return svc
 }
@@ -450,6 +453,9 @@ func (s *BillingCacheService) CheckBillingEligibility(ctx context.Context, user
 	if s.cfg.RunMode == config.RunModeSimple {
 		return nil
 	}
+	if s.circuitBreaker != nil && !s.circuitBreaker.Allow() {
+		return ErrBillingServiceUnavailable
+	}

 	// 判断计费模式
 	isSubscriptionMode := group != nil && group.IsSubscriptionType() && subscription != nil
@@ -465,9 +471,14 @@ func (s *BillingCacheService) CheckBillingEligibility(ctx context.Context, user
 func (s *BillingCacheService) checkBalanceEligibility(ctx context.Context, userID int64) error {
 	balance, err := s.GetUserBalance(ctx, userID)
 	if err != nil {
-		// 缓存/数据库错误，允许通过（降级处理）
-		log.Printf("Warning: get user balance failed, allowing request: %v", err)
-		return nil
+		if s.circuitBreaker != nil {
+			s.circuitBreaker.OnFailure(err)
+		}
+		log.Printf("ALERT: billing balance check failed for user %d: %v", userID, err)
+		return ErrBillingServiceUnavailable.WithCause(err)
+	}
+	if s.circuitBreaker != nil {
+		s.circuitBreaker.OnSuccess()
 	}

 	if balance <= 0 {
@@ -482,9 +493,14 @@ func (s *BillingCacheService) checkSubscriptionEligibility(ctx context.Context,
 	// 获取订阅缓存数据
 	subData, err := s.GetSubscriptionStatus(ctx, userID, group.ID)
 	if err != nil {
-		// 缓存/数据库错误，降级使用传入的subscription进行检查
-		log.Printf("Warning: get subscription cache failed, using fallback: %v", err)
-		return s.checkSubscriptionLimitsFallback(subscription, group)
+		if s.circuitBreaker != nil {
+			s.circuitBreaker.OnFailure(err)
+		}
+		log.Printf("ALERT: billing subscription check failed for user %d group %d: %v", userID, group.ID, err)
+		return ErrBillingServiceUnavailable.WithCause(err)
+	}
+	if s.circuitBreaker != nil {
+		s.circuitBreaker.OnSuccess()
 	}

 	// 检查订阅状态
@@ -513,27 +529,133 @@ func (s *BillingCacheService) checkSubscriptionEligibility(ctx context.Context,
 	return nil
 }

-// checkSubscriptionLimitsFallback 降级检查订阅限额
-func (s *BillingCacheService) checkSubscriptionLimitsFallback(subscription *UserSubscription, group *Group) error {
-	if subscription == nil {
-		return ErrSubscriptionInvalid
-	}
+type billingCircuitBreakerState int

-	if !subscription.IsActive() {
-		return ErrSubscriptionInvalid
-	}
+const (
+	billingCircuitClosed billingCircuitBreakerState = iota
+	billingCircuitOpen
+	billingCircuitHalfOpen
+)

-	if !subscription.CheckDailyLimit(group, 0) {
-		return ErrDailyLimitExceeded
-	}
-
-	if !subscription.CheckWeeklyLimit(group, 0) {
-		return ErrWeeklyLimitExceeded
-	}
-
-	if !subscription.CheckMonthlyLimit(group, 0) {
-		return ErrMonthlyLimitExceeded
-	}
-
-	return nil
+type billingCircuitBreaker struct {
+	mu                sync.Mutex
+	state             billingCircuitBreakerState
+	failures          int
+	openedAt          time.Time
+	failureThreshold  int
+	resetTimeout      time.Duration
+	halfOpenRequests  int
+	halfOpenRemaining int
+}
+
+func newBillingCircuitBreaker(cfg config.CircuitBreakerConfig) *billingCircuitBreaker {
+	if !cfg.Enabled {
+		return nil
+	}
+	resetTimeout := time.Duration(cfg.ResetTimeoutSeconds) * time.Second
+	if resetTimeout <= 0 {
+		resetTimeout = 30 * time.Second
+	}
+	halfOpen := cfg.HalfOpenRequests
+	if halfOpen <= 0 {
+		halfOpen = 1
+	}
+	threshold := cfg.FailureThreshold
+	if threshold <= 0 {
+		threshold = 5
+	}
+	return &billingCircuitBreaker{
+		state:            billingCircuitClosed,
+		failureThreshold: threshold,
+		resetTimeout:     resetTimeout,
+		halfOpenRequests: halfOpen,
+	}
+}
+
+func (b *billingCircuitBreaker) Allow() bool {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	switch b.state {
+	case billingCircuitClosed:
+		return true
+	case billingCircuitOpen:
+		if time.Since(b.openedAt) < b.resetTimeout {
+			return false
+		}
+		b.state = billingCircuitHalfOpen
+		b.halfOpenRemaining = b.halfOpenRequests
+		log.Printf("ALERT: billing circuit breaker entering half-open state")
+		fallthrough
+	case billingCircuitHalfOpen:
+		if b.halfOpenRemaining <= 0 {
+			return false
+		}
+		b.halfOpenRemaining--
+		return true
+	default:
+		return false
+	}
+}
+
+func (b *billingCircuitBreaker) OnFailure(err error) {
+	if b == nil {
+		return
+	}
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	switch b.state {
+	case billingCircuitOpen:
+		return
+	case billingCircuitHalfOpen:
+		b.state = billingCircuitOpen
+		b.openedAt = time.Now()
+		b.halfOpenRemaining = 0
+		log.Printf("ALERT: billing circuit breaker opened after half-open failure: %v", err)
+		return
+	default:
+		b.failures++
+		if b.failures >= b.failureThreshold {
+			b.state = billingCircuitOpen
+			b.openedAt = time.Now()
+			b.halfOpenRemaining = 0
+			log.Printf("ALERT: billing circuit breaker opened after %d failures: %v", b.failures, err)
+		}
+	}
+}
+
+func (b *billingCircuitBreaker) OnSuccess() {
+	if b == nil {
+		return
+	}
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	previousState := b.state
+	previousFailures := b.failures
+
+	b.state = billingCircuitClosed
+	b.failures = 0
+	b.halfOpenRemaining = 0
+
+	// 只有状态真正发生变化时才记录日志
+	if previousState != billingCircuitClosed {
+		log.Printf("ALERT: billing circuit breaker closed (was %s)", circuitStateString(previousState))
+	} else if previousFailures > 0 {
+		log.Printf("INFO: billing circuit breaker failures reset from %d", previousFailures)
+	}
+}
+
+func circuitStateString(state billingCircuitBreakerState) string {
+	switch state {
+	case billingCircuitClosed:
+		return "closed"
+	case billingCircuitOpen:
+		return "open"
+	case billingCircuitHalfOpen:
+		return "half-open"
+	default:
+		return "unknown"
+	}
 }
--- a/backend/internal/service/crs_sync_service.go
+++ b/backend/internal/service/crs_sync_service.go
@@ -8,12 +8,13 @@ import (
 	"fmt"
 	"io"
 	"net/http"
-	"net/url"
 	"strconv"
 	"strings"
 	"time"

+	"github.com/Wei-Shaw/sub2api/internal/config"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/httpclient"
+	"github.com/Wei-Shaw/sub2api/internal/util/urlvalidator"
 )

 type CRSSyncService struct {
@@ -22,6 +23,7 @@ type CRSSyncService struct {
 	oauthService       *OAuthService
 	openaiOAuthService *OpenAIOAuthService
 	geminiOAuthService *GeminiOAuthService
+	cfg                *config.Config
 }

 func NewCRSSyncService(
@@ -30,6 +32,7 @@ func NewCRSSyncService(
 	oauthService *OAuthService,
 	openaiOAuthService *OpenAIOAuthService,
 	geminiOAuthService *GeminiOAuthService,
+	cfg *config.Config,
 ) *CRSSyncService {
 	return &CRSSyncService{
 		accountRepo:        accountRepo,
@@ -37,6 +40,7 @@ func NewCRSSyncService(
 		oauthService:       oauthService,
 		openaiOAuthService: openaiOAuthService,
 		geminiOAuthService: geminiOAuthService,
+		cfg:                cfg,
 	}
 }

@@ -187,7 +191,10 @@ type crsGeminiAPIKeyAccount struct {
 }

 func (s *CRSSyncService) SyncFromCRS(ctx context.Context, input SyncFromCRSInput) (*SyncFromCRSResult, error) {
-	baseURL, err := normalizeBaseURL(input.BaseURL)
+	if s.cfg == nil {
+		return nil, errors.New("config is not available")
+	}
+	baseURL, err := normalizeBaseURL(input.BaseURL, s.cfg.Security.URLAllowlist.CRSHosts, s.cfg.Security.URLAllowlist.AllowPrivateHosts)
 	if err != nil {
 		return nil, err
 	}
@@ -196,7 +203,9 @@ func (s *CRSSyncService) SyncFromCRS(ctx context.Context, input SyncFromCRSInput
 	}

 	client, err := httpclient.GetClient(httpclient.Options{
-		Timeout: 20 * time.Second,
+		Timeout:            20 * time.Second,
+		ValidateResolvedIP: true,
+		AllowPrivateHosts:  s.cfg.Security.URLAllowlist.AllowPrivateHosts,
 	})
 	if err != nil {
 		client = &http.Client{Timeout: 20 * time.Second}
@@ -1055,17 +1064,18 @@ func mapCRSStatus(isActive bool, status string) string {
 	return "active"
 }

-func normalizeBaseURL(raw string) (string, error) {
-	trimmed := strings.TrimSpace(raw)
-	if trimmed == "" {
-		return "", errors.New("base_url is required")
+func normalizeBaseURL(raw string, allowlist []string, allowPrivate bool) (string, error) {
+	// 当 allowlist 为空时，不强制要求白名单（只进行基本的 URL 和 SSRF 验证）
+	requireAllowlist := len(allowlist) > 0
+	normalized, err := urlvalidator.ValidateHTTPSURL(raw, urlvalidator.ValidationOptions{
+		AllowedHosts:     allowlist,
+		RequireAllowlist: requireAllowlist,
+		AllowPrivate:     allowPrivate,
+	})
+	if err != nil {
+		return "", fmt.Errorf("invalid base_url: %w", err)
 	}
-	u, err := url.Parse(trimmed)
-	if err != nil || u.Scheme == "" || u.Host == "" {
-		return "", fmt.Errorf("invalid base_url: %s", trimmed)
-	}
-	u.Path = strings.TrimRight(u.Path, "/")
-	return strings.TrimRight(u.String(), "/"), nil
+	return normalized, nil
 }

 // cleanBaseURL removes trailing suffix from base_url in credentials
--- a/backend/internal/service/gateway_service.go
+++ b/backend/internal/service/gateway_service.go
@@ -15,11 +15,14 @@ import (
 	"regexp"
 	"sort"
 	"strings"
+	"sync/atomic"
 	"time"

 	"github.com/Wei-Shaw/sub2api/internal/config"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/claude"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/ctxkey"
+	"github.com/Wei-Shaw/sub2api/internal/util/responseheaders"
+	"github.com/Wei-Shaw/sub2api/internal/util/urlvalidator"
 	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"

@@ -30,6 +33,7 @@ const (
 	claudeAPIURL            = "https://api.anthropic.com/v1/messages?beta=true"
 	claudeAPICountTokensURL = "https://api.anthropic.com/v1/messages/count_tokens?beta=true"
 	stickySessionTTL        = time.Hour // 粘性会话TTL
+	defaultMaxLineSize      = 10 * 1024 * 1024
 	claudeCodeSystemPrompt  = "You are Claude Code, Anthropic's official CLI for Claude."
 )

@@ -1225,7 +1229,13 @@ func (s *GatewayService) buildUpstreamRequest(ctx context.Context, c *gin.Contex
 	targetURL := claudeAPIURL
 	if account.Type == AccountTypeAPIKey {
 		baseURL := account.GetBaseURL()
-		targetURL = baseURL + "/v1/messages"
+		if baseURL != "" {
+			validatedURL, err := s.validateUpstreamBaseURL(baseURL)
+			if err != nil {
+				return nil, err
+			}
+			targetURL = validatedURL + "/v1/messages"
+		}
 	}

 	// OAuth账号：应用统一指纹
@@ -1594,51 +1604,133 @@ func (s *GatewayService) handleStreamingResponse(ctx context.Context, resp *http
 	var firstTokenMs *int
 	scanner := bufio.NewScanner(resp.Body)
 	// 设置更大的buffer以处理长行
-	scanner.Buffer(make([]byte, 64*1024), 1024*1024)
+	maxLineSize := defaultMaxLineSize
+	if s.cfg != nil && s.cfg.Gateway.MaxLineSize > 0 {
+		maxLineSize = s.cfg.Gateway.MaxLineSize
+	}
+	scanner.Buffer(make([]byte, 64*1024), maxLineSize)
+
+	type scanEvent struct {
+		line string
+		err  error
+	}
+	// 独立 goroutine 读取上游，避免读取阻塞导致超时/keepalive无法处理
+	events := make(chan scanEvent, 16)
+	done := make(chan struct{})
+	sendEvent := func(ev scanEvent) bool {
+		select {
+		case events <- ev:
+			return true
+		case <-done:
+			return false
+		}
+	}
+	var lastReadAt int64
+	atomic.StoreInt64(&lastReadAt, time.Now().UnixNano())
+	go func() {
+		defer close(events)
+		for scanner.Scan() {
+			atomic.StoreInt64(&lastReadAt, time.Now().UnixNano())
+			if !sendEvent(scanEvent{line: scanner.Text()}) {
+				return
+			}
+		}
+		if err := scanner.Err(); err != nil {
+			_ = sendEvent(scanEvent{err: err})
+		}
+	}()
+	defer close(done)
+
+	streamInterval := time.Duration(0)
+	if s.cfg != nil && s.cfg.Gateway.StreamDataIntervalTimeout > 0 {
+		streamInterval = time.Duration(s.cfg.Gateway.StreamDataIntervalTimeout) * time.Second
+	}
+	// 仅监控上游数据间隔超时，避免下游写入阻塞导致误判
+	var intervalTicker *time.Ticker
+	if streamInterval > 0 {
+		intervalTicker = time.NewTicker(streamInterval)
+		defer intervalTicker.Stop()
+	}
+	var intervalCh <-chan time.Time
+	if intervalTicker != nil {
+		intervalCh = intervalTicker.C
+	}
+
+	// 仅发送一次错误事件，避免多次写入导致协议混乱（写失败时尽力通知客户端）
+	errorEventSent := false
+	sendErrorEvent := func(reason string) {
+		if errorEventSent {
+			return
+		}
+		errorEventSent = true
+		_, _ = fmt.Fprintf(w, "event: error\ndata: {\"error\":\"%s\"}\n\n", reason)
+		flusher.Flush()
+	}

 	needModelReplace := originalModel != mappedModel

-	for scanner.Scan() {
-		line := scanner.Text()
-		if line == "event: error" {
-			return nil, errors.New("have error in stream")
-		}
-
-		// Extract data from SSE line (supports both "data: " and "data:" formats)
-		if sseDataRe.MatchString(line) {
-			data := sseDataRe.ReplaceAllString(line, "")
-
-			// 如果有模型映射，替换响应中的model字段
-			if needModelReplace {
-				line = s.replaceModelInSSELine(line, mappedModel, originalModel)
+	for {
+		select {
+		case ev, ok := <-events:
+			if !ok {
+				return &streamingResult{usage: usage, firstTokenMs: firstTokenMs}, nil
+			}
+			if ev.err != nil {
+				if errors.Is(ev.err, bufio.ErrTooLong) {
+					log.Printf("SSE line too long: account=%d max_size=%d error=%v", account.ID, maxLineSize, ev.err)
+					sendErrorEvent("response_too_large")
+					return &streamingResult{usage: usage, firstTokenMs: firstTokenMs}, ev.err
+				}
+				sendErrorEvent("stream_read_error")
+				return &streamingResult{usage: usage, firstTokenMs: firstTokenMs}, fmt.Errorf("stream read error: %w", ev.err)
+			}
+			line := ev.line
+			if line == "event: error" {
+				return nil, errors.New("have error in stream")
 			}

-			// 转发行
-			if _, err := fmt.Fprintf(w, "%s\n", line); err != nil {
-				return &streamingResult{usage: usage, firstTokenMs: firstTokenMs}, err
-			}
-			flusher.Flush()
+			// Extract data from SSE line (supports both "data: " and "data:" formats)
+			if sseDataRe.MatchString(line) {
+				data := sseDataRe.ReplaceAllString(line, "")

-			// 记录首字时间：第一个有效的 content_block_delta 或 message_start
-			if firstTokenMs == nil && data != "" && data != "[DONE]" {
-				ms := int(time.Since(startTime).Milliseconds())
-				firstTokenMs = &ms
+				// 如果有模型映射，替换响应中的model字段
+				if needModelReplace {
+					line = s.replaceModelInSSELine(line, mappedModel, originalModel)
+				}
+
+				// 转发行
+				if _, err := fmt.Fprintf(w, "%s\n", line); err != nil {
+					sendErrorEvent("write_failed")
+					return &streamingResult{usage: usage, firstTokenMs: firstTokenMs}, err
+				}
+				flusher.Flush()
+
+				// 记录首字时间：第一个有效的 content_block_delta 或 message_start
+				if firstTokenMs == nil && data != "" && data != "[DONE]" {
+					ms := int(time.Since(startTime).Milliseconds())
+					firstTokenMs = &ms
+				}
+				s.parseSSEUsage(data, usage)
+			} else {
+				// 非 data 行直接转发
+				if _, err := fmt.Fprintf(w, "%s\n", line); err != nil {
+					sendErrorEvent("write_failed")
+					return &streamingResult{usage: usage, firstTokenMs: firstTokenMs}, err
+				}
+				flusher.Flush()
 			}
-			s.parseSSEUsage(data, usage)
-		} else {
-			// 非 data 行直接转发
-			if _, err := fmt.Fprintf(w, "%s\n", line); err != nil {
-				return &streamingResult{usage: usage, firstTokenMs: firstTokenMs}, err
+
+		case <-intervalCh:
+			lastRead := time.Unix(0, atomic.LoadInt64(&lastReadAt))
+			if time.Since(lastRead) < streamInterval {
+				continue
 			}
-			flusher.Flush()
+			log.Printf("Stream data interval timeout: account=%d model=%s interval=%s", account.ID, originalModel, streamInterval)
+			sendErrorEvent("stream_timeout")
+			return &streamingResult{usage: usage, firstTokenMs: firstTokenMs}, fmt.Errorf("stream data interval timeout")
 		}
 	}

-	if err := scanner.Err(); err != nil {
-		return &streamingResult{usage: usage, firstTokenMs: firstTokenMs}, fmt.Errorf("stream read error: %w", err)
-	}
-
-	return &streamingResult{usage: usage, firstTokenMs: firstTokenMs}, nil
 }

 // replaceModelInSSELine 替换SSE数据行中的model字段
@@ -1743,12 +1835,7 @@ func (s *GatewayService) handleNonStreamingResponse(ctx context.Context, resp *h
 		body = s.replaceModelInResponseBody(body, mappedModel, originalModel)
 	}

-	// 透传响应头
-	for key, values := range resp.Header {
-		for _, value := range values {
-			c.Header(key, value)
-		}
-	}
+	responseheaders.WriteFilteredHeaders(c.Writer.Header(), resp.Header, s.cfg.Security.ResponseHeaders)

 	// 写入响应
 	c.Data(resp.StatusCode, "application/json", body)
@@ -2020,7 +2107,13 @@ func (s *GatewayService) buildCountTokensRequest(ctx context.Context, c *gin.Con
 	targetURL := claudeAPICountTokensURL
 	if account.Type == AccountTypeAPIKey {
 		baseURL := account.GetBaseURL()
-		targetURL = baseURL + "/v1/messages/count_tokens"
+		if baseURL != "" {
+			validatedURL, err := s.validateUpstreamBaseURL(baseURL)
+			if err != nil {
+				return nil, err
+			}
+			targetURL = validatedURL + "/v1/messages/count_tokens"
+		}
 	}

 	// OAuth 账号：应用统一指纹和重写 userID
@@ -2100,6 +2193,18 @@ func (s *GatewayService) countTokensError(c *gin.Context, status int, errType, m
 	})
 }

+func (s *GatewayService) validateUpstreamBaseURL(raw string) (string, error) {
+	normalized, err := urlvalidator.ValidateHTTPSURL(raw, urlvalidator.ValidationOptions{
+		AllowedHosts:     s.cfg.Security.URLAllowlist.UpstreamHosts,
+		RequireAllowlist: true,
+		AllowPrivate:     s.cfg.Security.URLAllowlist.AllowPrivateHosts,
+	})
+	if err != nil {
+		return "", fmt.Errorf("invalid base_url: %w", err)
+	}
+	return normalized, nil
+}
+
 // GetAvailableModels returns the list of models available for a group
 // It aggregates model_mapping keys from all schedulable accounts in the group
 func (s *GatewayService) GetAvailableModels(ctx context.Context, groupID *int64, platform string) []string {
--- a/backend/internal/service/gemini_messages_compat_service.go
+++ b/backend/internal/service/gemini_messages_compat_service.go
@@ -18,9 +18,12 @@ import (
 	"strings"
 	"time"

+	"github.com/Wei-Shaw/sub2api/internal/config"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/ctxkey"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/geminicli"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/googleapi"
+	"github.com/Wei-Shaw/sub2api/internal/util/responseheaders"
+	"github.com/Wei-Shaw/sub2api/internal/util/urlvalidator"

 	"github.com/gin-gonic/gin"
 )
@@ -41,6 +44,7 @@ type GeminiMessagesCompatService struct {
 	rateLimitService          *RateLimitService
 	httpUpstream              HTTPUpstream
 	antigravityGatewayService *AntigravityGatewayService
+	cfg                       *config.Config
 }

 func NewGeminiMessagesCompatService(
@@ -51,6 +55,7 @@ func NewGeminiMessagesCompatService(
 	rateLimitService *RateLimitService,
 	httpUpstream HTTPUpstream,
 	antigravityGatewayService *AntigravityGatewayService,
+	cfg *config.Config,
 ) *GeminiMessagesCompatService {
 	return &GeminiMessagesCompatService{
 		accountRepo:               accountRepo,
@@ -60,6 +65,7 @@ func NewGeminiMessagesCompatService(
 		rateLimitService:          rateLimitService,
 		httpUpstream:              httpUpstream,
 		antigravityGatewayService: antigravityGatewayService,
+		cfg:                       cfg,
 	}
 }

@@ -230,6 +236,18 @@ func (s *GeminiMessagesCompatService) GetAntigravityGatewayService() *Antigravit
 	return s.antigravityGatewayService
 }

+func (s *GeminiMessagesCompatService) validateUpstreamBaseURL(raw string) (string, error) {
+	normalized, err := urlvalidator.ValidateHTTPSURL(raw, urlvalidator.ValidationOptions{
+		AllowedHosts:     s.cfg.Security.URLAllowlist.UpstreamHosts,
+		RequireAllowlist: true,
+		AllowPrivate:     s.cfg.Security.URLAllowlist.AllowPrivateHosts,
+	})
+	if err != nil {
+		return "", fmt.Errorf("invalid base_url: %w", err)
+	}
+	return normalized, nil
+}
+
 // HasAntigravityAccounts 检查是否有可用的 antigravity 账户
 func (s *GeminiMessagesCompatService) HasAntigravityAccounts(ctx context.Context, groupID *int64) (bool, error) {
 	var accounts []Account
@@ -381,16 +399,20 @@ func (s *GeminiMessagesCompatService) Forward(ctx context.Context, c *gin.Contex
 				return nil, "", errors.New("gemini api_key not configured")
 			}

-			baseURL := strings.TrimRight(account.GetCredential("base_url"), "/")
+			baseURL := strings.TrimSpace(account.GetCredential("base_url"))
 			if baseURL == "" {
 				baseURL = geminicli.AIStudioBaseURL
 			}
+			normalizedBaseURL, err := s.validateUpstreamBaseURL(baseURL)
+			if err != nil {
+				return nil, "", err
+			}

 			action := "generateContent"
 			if req.Stream {
 				action = "streamGenerateContent"
 			}
-			fullURL := fmt.Sprintf("%s/v1beta/models/%s:%s", strings.TrimRight(baseURL, "/"), mappedModel, action)
+			fullURL := fmt.Sprintf("%s/v1beta/models/%s:%s", strings.TrimRight(normalizedBaseURL, "/"), mappedModel, action)
 			if req.Stream {
 				fullURL += "?alt=sse"
 			}
@@ -427,7 +449,11 @@ func (s *GeminiMessagesCompatService) Forward(ctx context.Context, c *gin.Contex
 			// 2. Without project_id -> AI Studio API (direct OAuth, like API key but with Bearer token)
 			if projectID != "" {
 				// Mode 1: Code Assist API
-				fullURL := fmt.Sprintf("%s/v1internal:%s", geminicli.GeminiCliBaseURL, action)
+				baseURL, err := s.validateUpstreamBaseURL(geminicli.GeminiCliBaseURL)
+				if err != nil {
+					return nil, "", err
+				}
+				fullURL := fmt.Sprintf("%s/v1internal:%s", strings.TrimRight(baseURL, "/"), action)
 				if useUpstreamStream {
 					fullURL += "?alt=sse"
 				}
@@ -453,12 +479,16 @@ func (s *GeminiMessagesCompatService) Forward(ctx context.Context, c *gin.Contex
 				return upstreamReq, "x-request-id", nil
 			} else {
 				// Mode 2: AI Studio API with OAuth (like API key mode, but using Bearer token)
-				baseURL := strings.TrimRight(account.GetCredential("base_url"), "/")
+				baseURL := strings.TrimSpace(account.GetCredential("base_url"))
 				if baseURL == "" {
 					baseURL = geminicli.AIStudioBaseURL
 				}
+				normalizedBaseURL, err := s.validateUpstreamBaseURL(baseURL)
+				if err != nil {
+					return nil, "", err
+				}

-				fullURL := fmt.Sprintf("%s/v1beta/models/%s:%s", baseURL, mappedModel, action)
+				fullURL := fmt.Sprintf("%s/v1beta/models/%s:%s", strings.TrimRight(normalizedBaseURL, "/"), mappedModel, action)
 				if useUpstreamStream {
 					fullURL += "?alt=sse"
 				}
@@ -650,12 +680,16 @@ func (s *GeminiMessagesCompatService) ForwardNative(ctx context.Context, c *gin.
 				return nil, "", errors.New("gemini api_key not configured")
 			}

-			baseURL := strings.TrimRight(account.GetCredential("base_url"), "/")
+			baseURL := strings.TrimSpace(account.GetCredential("base_url"))
 			if baseURL == "" {
 				baseURL = geminicli.AIStudioBaseURL
 			}
+			normalizedBaseURL, err := s.validateUpstreamBaseURL(baseURL)
+			if err != nil {
+				return nil, "", err
+			}

-			fullURL := fmt.Sprintf("%s/v1beta/models/%s:%s", strings.TrimRight(baseURL, "/"), mappedModel, upstreamAction)
+			fullURL := fmt.Sprintf("%s/v1beta/models/%s:%s", strings.TrimRight(normalizedBaseURL, "/"), mappedModel, upstreamAction)
 			if useUpstreamStream {
 				fullURL += "?alt=sse"
 			}
@@ -687,7 +721,11 @@ func (s *GeminiMessagesCompatService) ForwardNative(ctx context.Context, c *gin.
 			// 2. Without project_id -> AI Studio API (direct OAuth, like API key but with Bearer token)
 			if projectID != "" && !forceAIStudio {
 				// Mode 1: Code Assist API
-				fullURL := fmt.Sprintf("%s/v1internal:%s", geminicli.GeminiCliBaseURL, upstreamAction)
+				baseURL, err := s.validateUpstreamBaseURL(geminicli.GeminiCliBaseURL)
+				if err != nil {
+					return nil, "", err
+				}
+				fullURL := fmt.Sprintf("%s/v1internal:%s", strings.TrimRight(baseURL, "/"), upstreamAction)
 				if useUpstreamStream {
 					fullURL += "?alt=sse"
 				}
@@ -713,12 +751,16 @@ func (s *GeminiMessagesCompatService) ForwardNative(ctx context.Context, c *gin.
 				return upstreamReq, "x-request-id", nil
 			} else {
 				// Mode 2: AI Studio API with OAuth (like API key mode, but using Bearer token)
-				baseURL := strings.TrimRight(account.GetCredential("base_url"), "/")
+				baseURL := strings.TrimSpace(account.GetCredential("base_url"))
 				if baseURL == "" {
 					baseURL = geminicli.AIStudioBaseURL
 				}
+				normalizedBaseURL, err := s.validateUpstreamBaseURL(baseURL)
+				if err != nil {
+					return nil, "", err
+				}

-				fullURL := fmt.Sprintf("%s/v1beta/models/%s:%s", baseURL, mappedModel, upstreamAction)
+				fullURL := fmt.Sprintf("%s/v1beta/models/%s:%s", strings.TrimRight(normalizedBaseURL, "/"), mappedModel, upstreamAction)
 				if useUpstreamStream {
 					fullURL += "?alt=sse"
 				}
@@ -1652,6 +1694,8 @@ func (s *GeminiMessagesCompatService) handleNativeNonStreamingResponse(c *gin.Co
 		_ = json.Unmarshal(respBody, &parsed)
 	}

+	responseheaders.WriteFilteredHeaders(c.Writer.Header(), resp.Header, s.cfg.Security.ResponseHeaders)
+
 	contentType := resp.Header.Get("Content-Type")
 	if contentType == "" {
 		contentType = "application/json"
@@ -1773,11 +1817,15 @@ func (s *GeminiMessagesCompatService) ForwardAIStudioGET(ctx context.Context, ac
 		return nil, errors.New("invalid path")
 	}

-	baseURL := strings.TrimRight(account.GetCredential("base_url"), "/")
+	baseURL := strings.TrimSpace(account.GetCredential("base_url"))
 	if baseURL == "" {
 		baseURL = geminicli.AIStudioBaseURL
 	}
-	fullURL := strings.TrimRight(baseURL, "/") + path
+	normalizedBaseURL, err := s.validateUpstreamBaseURL(baseURL)
+	if err != nil {
+		return nil, err
+	}
+	fullURL := strings.TrimRight(normalizedBaseURL, "/") + path

 	var proxyURL string
 	if account.ProxyID != nil && account.Proxy != nil {
@@ -1816,9 +1864,14 @@ func (s *GeminiMessagesCompatService) ForwardAIStudioGET(ctx context.Context, ac
 	defer func() { _ = resp.Body.Close() }()

 	body, _ := io.ReadAll(io.LimitReader(resp.Body, 8<<20))
+	wwwAuthenticate := resp.Header.Get("Www-Authenticate")
+	filteredHeaders := responseheaders.FilterHeaders(resp.Header, s.cfg.Security.ResponseHeaders)
+	if wwwAuthenticate != "" {
+		filteredHeaders.Set("Www-Authenticate", wwwAuthenticate)
+	}
 	return &UpstreamHTTPResult{
 		StatusCode: resp.StatusCode,
-		Headers:    resp.Header.Clone(),
+		Headers:    filteredHeaders,
 		Body:       body,
 	}, nil
 }
--- a/backend/internal/service/gemini_oauth_service.go
+++ b/backend/internal/service/gemini_oauth_service.go
@@ -1000,8 +1000,9 @@ func fetchProjectIDFromResourceManager(ctx context.Context, accessToken, proxyUR
 	req.Header.Set("User-Agent", geminicli.GeminiCLIUserAgent)

 	client, err := httpclient.GetClient(httpclient.Options{
-		ProxyURL: strings.TrimSpace(proxyURL),
-		Timeout:  30 * time.Second,
+		ProxyURL:           strings.TrimSpace(proxyURL),
+		Timeout:            30 * time.Second,
+		ValidateResolvedIP: true,
 	})
 	if err != nil {
 		client = &http.Client{Timeout: 30 * time.Second}
--- a/backend/internal/service/openai_gateway_service.go
+++ b/backend/internal/service/openai_gateway_service.go
@@ -16,9 +16,12 @@ import (
 	"sort"
 	"strconv"
 	"strings"
+	"sync/atomic"
 	"time"

 	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/Wei-Shaw/sub2api/internal/util/responseheaders"
+	"github.com/Wei-Shaw/sub2api/internal/util/urlvalidator"
 	"github.com/gin-gonic/gin"
 )

@@ -630,10 +633,14 @@ func (s *OpenAIGatewayService) buildUpstreamRequest(ctx context.Context, c *gin.
 	case AccountTypeAPIKey:
 		// API Key accounts use Platform API or custom base URL
 		baseURL := account.GetOpenAIBaseURL()
-		if baseURL != "" {
-			targetURL = baseURL + "/responses"
-		} else {
+		if baseURL == "" {
 			targetURL = openaiPlatformAPIURL
+		} else {
+			validatedURL, err := s.validateUpstreamBaseURL(baseURL)
+			if err != nil {
+				return nil, err
+			}
+			targetURL = validatedURL + "/responses"
 		}
 	default:
 		targetURL = openaiPlatformAPIURL
@@ -775,48 +782,158 @@ func (s *OpenAIGatewayService) handleStreamingResponse(ctx context.Context, resp
 	usage := &OpenAIUsage{}
 	var firstTokenMs *int
 	scanner := bufio.NewScanner(resp.Body)
-	scanner.Buffer(make([]byte, 64*1024), 1024*1024)
+	maxLineSize := defaultMaxLineSize
+	if s.cfg != nil && s.cfg.Gateway.MaxLineSize > 0 {
+		maxLineSize = s.cfg.Gateway.MaxLineSize
+	}
+	scanner.Buffer(make([]byte, 64*1024), maxLineSize)
+
+	type scanEvent struct {
+		line string
+		err  error
+	}
+	// 独立 goroutine 读取上游，避免读取阻塞影响 keepalive/超时处理
+	events := make(chan scanEvent, 16)
+	done := make(chan struct{})
+	sendEvent := func(ev scanEvent) bool {
+		select {
+		case events <- ev:
+			return true
+		case <-done:
+			return false
+		}
+	}
+	var lastReadAt int64
+	atomic.StoreInt64(&lastReadAt, time.Now().UnixNano())
+	go func() {
+		defer close(events)
+		for scanner.Scan() {
+			atomic.StoreInt64(&lastReadAt, time.Now().UnixNano())
+			if !sendEvent(scanEvent{line: scanner.Text()}) {
+				return
+			}
+		}
+		if err := scanner.Err(); err != nil {
+			_ = sendEvent(scanEvent{err: err})
+		}
+	}()
+	defer close(done)
+
+	streamInterval := time.Duration(0)
+	if s.cfg != nil && s.cfg.Gateway.StreamDataIntervalTimeout > 0 {
+		streamInterval = time.Duration(s.cfg.Gateway.StreamDataIntervalTimeout) * time.Second
+	}
+	// 仅监控上游数据间隔超时，不被下游写入阻塞影响
+	var intervalTicker *time.Ticker
+	if streamInterval > 0 {
+		intervalTicker = time.NewTicker(streamInterval)
+		defer intervalTicker.Stop()
+	}
+	var intervalCh <-chan time.Time
+	if intervalTicker != nil {
+		intervalCh = intervalTicker.C
+	}
+
+	keepaliveInterval := time.Duration(0)
+	if s.cfg != nil && s.cfg.Gateway.StreamKeepaliveInterval > 0 {
+		keepaliveInterval = time.Duration(s.cfg.Gateway.StreamKeepaliveInterval) * time.Second
+	}
+	// 下游 keepalive 仅用于防止代理空闲断开
+	var keepaliveTicker *time.Ticker
+	if keepaliveInterval > 0 {
+		keepaliveTicker = time.NewTicker(keepaliveInterval)
+		defer keepaliveTicker.Stop()
+	}
+	var keepaliveCh <-chan time.Time
+	if keepaliveTicker != nil {
+		keepaliveCh = keepaliveTicker.C
+	}
+	// 记录上次收到上游数据的时间，用于控制 keepalive 发送频率
+	lastDataAt := time.Now()
+
+	// 仅发送一次错误事件，避免多次写入导致协议混乱（写失败时尽力通知客户端）
+	errorEventSent := false
+	sendErrorEvent := func(reason string) {
+		if errorEventSent {
+			return
+		}
+		errorEventSent = true
+		_, _ = fmt.Fprintf(w, "event: error\ndata: {\"error\":\"%s\"}\n\n", reason)
+		flusher.Flush()
+	}

 	needModelReplace := originalModel != mappedModel

-	for scanner.Scan() {
-		line := scanner.Text()
-
-		// Extract data from SSE line (supports both "data: " and "data:" formats)
-		if openaiSSEDataRe.MatchString(line) {
-			data := openaiSSEDataRe.ReplaceAllString(line, "")
-
-			// Replace model in response if needed
-			if needModelReplace {
-				line = s.replaceModelInSSELine(line, mappedModel, originalModel)
+	for {
+		select {
+		case ev, ok := <-events:
+			if !ok {
+				return &openaiStreamingResult{usage: usage, firstTokenMs: firstTokenMs}, nil
+			}
+			if ev.err != nil {
+				if errors.Is(ev.err, bufio.ErrTooLong) {
+					log.Printf("SSE line too long: account=%d max_size=%d error=%v", account.ID, maxLineSize, ev.err)
+					sendErrorEvent("response_too_large")
+					return &openaiStreamingResult{usage: usage, firstTokenMs: firstTokenMs}, ev.err
+				}
+				sendErrorEvent("stream_read_error")
+				return &openaiStreamingResult{usage: usage, firstTokenMs: firstTokenMs}, fmt.Errorf("stream read error: %w", ev.err)
 			}

-			// Forward line
-			if _, err := fmt.Fprintf(w, "%s\n", line); err != nil {
-				return &openaiStreamingResult{usage: usage, firstTokenMs: firstTokenMs}, err
-			}
-			flusher.Flush()
+			line := ev.line
+			lastDataAt = time.Now()

-			// Record first token time
-			if firstTokenMs == nil && data != "" && data != "[DONE]" {
-				ms := int(time.Since(startTime).Milliseconds())
-				firstTokenMs = &ms
+			// Extract data from SSE line (supports both "data: " and "data:" formats)
+			if openaiSSEDataRe.MatchString(line) {
+				data := openaiSSEDataRe.ReplaceAllString(line, "")
+
+				// Replace model in response if needed
+				if needModelReplace {
+					line = s.replaceModelInSSELine(line, mappedModel, originalModel)
+				}
+
+				// Forward line
+				if _, err := fmt.Fprintf(w, "%s\n", line); err != nil {
+					sendErrorEvent("write_failed")
+					return &openaiStreamingResult{usage: usage, firstTokenMs: firstTokenMs}, err
+				}
+				flusher.Flush()
+
+				// Record first token time
+				if firstTokenMs == nil && data != "" && data != "[DONE]" {
+					ms := int(time.Since(startTime).Milliseconds())
+					firstTokenMs = &ms
+				}
+				s.parseSSEUsage(data, usage)
+			} else {
+				// Forward non-data lines as-is
+				if _, err := fmt.Fprintf(w, "%s\n", line); err != nil {
+					sendErrorEvent("write_failed")
+					return &openaiStreamingResult{usage: usage, firstTokenMs: firstTokenMs}, err
+				}
+				flusher.Flush()
 			}
-			s.parseSSEUsage(data, usage)
-		} else {
-			// Forward non-data lines as-is
-			if _, err := fmt.Fprintf(w, "%s\n", line); err != nil {
+
+		case <-intervalCh:
+			lastRead := time.Unix(0, atomic.LoadInt64(&lastReadAt))
+			if time.Since(lastRead) < streamInterval {
+				continue
+			}
+			log.Printf("Stream data interval timeout: account=%d model=%s interval=%s", account.ID, originalModel, streamInterval)
+			sendErrorEvent("stream_timeout")
+			return &openaiStreamingResult{usage: usage, firstTokenMs: firstTokenMs}, fmt.Errorf("stream data interval timeout")
+
+		case <-keepaliveCh:
+			if time.Since(lastDataAt) < keepaliveInterval {
+				continue
+			}
+			if _, err := fmt.Fprint(w, ":\n\n"); err != nil {
 				return &openaiStreamingResult{usage: usage, firstTokenMs: firstTokenMs}, err
 			}
 			flusher.Flush()
 		}
 	}

-	if err := scanner.Err(); err != nil {
-		return &openaiStreamingResult{usage: usage, firstTokenMs: firstTokenMs}, fmt.Errorf("stream read error: %w", err)
-	}
-
-	return &openaiStreamingResult{usage: usage, firstTokenMs: firstTokenMs}, nil
 }

 func (s *OpenAIGatewayService) replaceModelInSSELine(line, fromModel, toModel string) string {
@@ -911,18 +1028,25 @@ func (s *OpenAIGatewayService) handleNonStreamingResponse(ctx context.Context, r
 		body = s.replaceModelInResponseBody(body, mappedModel, originalModel)
 	}

-	// Pass through headers
-	for key, values := range resp.Header {
-		for _, value := range values {
-			c.Header(key, value)
-		}
-	}
+	responseheaders.WriteFilteredHeaders(c.Writer.Header(), resp.Header, s.cfg.Security.ResponseHeaders)

 	c.Data(resp.StatusCode, "application/json", body)

 	return usage, nil
 }

+func (s *OpenAIGatewayService) validateUpstreamBaseURL(raw string) (string, error) {
+	normalized, err := urlvalidator.ValidateHTTPSURL(raw, urlvalidator.ValidationOptions{
+		AllowedHosts:     s.cfg.Security.URLAllowlist.UpstreamHosts,
+		RequireAllowlist: true,
+		AllowPrivate:     s.cfg.Security.URLAllowlist.AllowPrivateHosts,
+	})
+	if err != nil {
+		return "", fmt.Errorf("invalid base_url: %w", err)
+	}
+	return normalized, nil
+}
+
 func (s *OpenAIGatewayService) replaceModelInResponseBody(body []byte, fromModel, toModel string) []byte {
 	var resp map[string]any
 	if err := json.Unmarshal(body, &resp); err != nil {
--- a/backend/internal/service/openai_gateway_service_test.go
+++ b/backend/internal/service/openai_gateway_service_test.go
@@ -0,0 +1,90 @@
+package service
+
+import (
+	"bufio"
+	"errors"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/gin-gonic/gin"
+)
+
+func TestOpenAIStreamingTimeout(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	cfg := &config.Config{
+		Gateway: config.GatewayConfig{
+			StreamDataIntervalTimeout: 1,
+			StreamKeepaliveInterval:   0,
+			MaxLineSize:               defaultMaxLineSize,
+		},
+	}
+	svc := &OpenAIGatewayService{cfg: cfg}
+
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodPost, "/", nil)
+
+	pr, pw := io.Pipe()
+	resp := &http.Response{
+		StatusCode: http.StatusOK,
+		Body:       pr,
+		Header:     http.Header{},
+	}
+
+	start := time.Now()
+	_, err := svc.handleStreamingResponse(c.Request.Context(), resp, c, &Account{ID: 1}, start, "model", "model")
+	_ = pw.Close()
+	_ = pr.Close()
+
+	if err == nil || !strings.Contains(err.Error(), "stream data interval timeout") {
+		t.Fatalf("expected stream timeout error, got %v", err)
+	}
+	if !strings.Contains(rec.Body.String(), "stream_timeout") {
+		t.Fatalf("expected stream_timeout SSE error, got %q", rec.Body.String())
+	}
+}
+
+func TestOpenAIStreamingTooLong(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	cfg := &config.Config{
+		Gateway: config.GatewayConfig{
+			StreamDataIntervalTimeout: 0,
+			StreamKeepaliveInterval:   0,
+			MaxLineSize:               64 * 1024,
+		},
+	}
+	svc := &OpenAIGatewayService{cfg: cfg}
+
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodPost, "/", nil)
+
+	pr, pw := io.Pipe()
+	resp := &http.Response{
+		StatusCode: http.StatusOK,
+		Body:       pr,
+		Header:     http.Header{},
+	}
+
+	go func() {
+		defer func() { _ = pw.Close() }()
+		// 写入超过 MaxLineSize 的单行数据，触发 ErrTooLong
+		payload := "data: " + strings.Repeat("a", 128*1024) + "\n"
+		_, _ = pw.Write([]byte(payload))
+	}()
+
+	_, err := svc.handleStreamingResponse(c.Request.Context(), resp, c, &Account{ID: 2}, time.Now(), "model", "model")
+	_ = pr.Close()
+
+	if !errors.Is(err, bufio.ErrTooLong) {
+		t.Fatalf("expected ErrTooLong, got %v", err)
+	}
+	if !strings.Contains(rec.Body.String(), "response_too_large") {
+		t.Fatalf("expected response_too_large SSE error, got %q", rec.Body.String())
+	}
+}
--- a/backend/internal/service/pricing_service.go
+++ b/backend/internal/service/pricing_service.go
@@ -16,6 +16,7 @@ import (

 	"github.com/Wei-Shaw/sub2api/internal/config"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/openai"
+	"github.com/Wei-Shaw/sub2api/internal/util/urlvalidator"
 )

 var (
@@ -211,16 +212,35 @@ func (s *PricingService) syncWithRemote() error {

 // downloadPricingData 从远程下载价格数据
 func (s *PricingService) downloadPricingData() error {
-	log.Printf("[Pricing] Downloading from %s", s.cfg.Pricing.RemoteURL)
+	remoteURL, err := s.validatePricingURL(s.cfg.Pricing.RemoteURL)
+	if err != nil {
+		return err
+	}
+	log.Printf("[Pricing] Downloading from %s", remoteURL)

 	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
 	defer cancel()

-	body, err := s.remoteClient.FetchPricingJSON(ctx, s.cfg.Pricing.RemoteURL)
+	var expectedHash string
+	if strings.TrimSpace(s.cfg.Pricing.HashURL) != "" {
+		expectedHash, err = s.fetchRemoteHash()
+		if err != nil {
+			return fmt.Errorf("fetch remote hash: %w", err)
+		}
+	}
+
+	body, err := s.remoteClient.FetchPricingJSON(ctx, remoteURL)
 	if err != nil {
 		return fmt.Errorf("download failed: %w", err)
 	}

+	if expectedHash != "" {
+		actualHash := sha256.Sum256(body)
+		if !strings.EqualFold(expectedHash, hex.EncodeToString(actualHash[:])) {
+			return fmt.Errorf("pricing hash mismatch")
+		}
+	}
+
 	// 解析JSON数据（使用灵活的解析方式）
 	data, err := s.parsePricingData(body)
 	if err != nil {
@@ -373,10 +393,31 @@ func (s *PricingService) useFallbackPricing() error {

 // fetchRemoteHash 从远程获取哈希值
 func (s *PricingService) fetchRemoteHash() (string, error) {
+	hashURL, err := s.validatePricingURL(s.cfg.Pricing.HashURL)
+	if err != nil {
+		return "", err
+	}
+
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()

-	return s.remoteClient.FetchHashText(ctx, s.cfg.Pricing.HashURL)
+	hash, err := s.remoteClient.FetchHashText(ctx, hashURL)
+	if err != nil {
+		return "", err
+	}
+	return strings.TrimSpace(hash), nil
+}
+
+func (s *PricingService) validatePricingURL(raw string) (string, error) {
+	normalized, err := urlvalidator.ValidateHTTPSURL(raw, urlvalidator.ValidationOptions{
+		AllowedHosts:     s.cfg.Security.URLAllowlist.PricingHosts,
+		RequireAllowlist: true,
+		AllowPrivate:     s.cfg.Security.URLAllowlist.AllowPrivateHosts,
+	})
+	if err != nil {
+		return "", fmt.Errorf("invalid pricing url: %w", err)
+	}
+	return normalized, nil
 }

 // computeFileHash 计算文件哈希
--- a/backend/internal/service/setting_service.go
+++ b/backend/internal/service/setting_service.go
@@ -221,21 +221,23 @@ func (s *SettingService) InitializeDefaultSettings(ctx context.Context) error {
 // parseSettings 解析设置到结构体
 func (s *SettingService) parseSettings(settings map[string]string) *SystemSettings {
 	result := &SystemSettings{
-		RegistrationEnabled: settings[SettingKeyRegistrationEnabled] == "true",
-		EmailVerifyEnabled:  settings[SettingKeyEmailVerifyEnabled] == "true",
-		SMTPHost:            settings[SettingKeySMTPHost],
-		SMTPUsername:        settings[SettingKeySMTPUsername],
-		SMTPFrom:            settings[SettingKeySMTPFrom],
-		SMTPFromName:        settings[SettingKeySMTPFromName],
-		SMTPUseTLS:          settings[SettingKeySMTPUseTLS] == "true",
-		TurnstileEnabled:    settings[SettingKeyTurnstileEnabled] == "true",
-		TurnstileSiteKey:    settings[SettingKeyTurnstileSiteKey],
-		SiteName:            s.getStringOrDefault(settings, SettingKeySiteName, "Sub2API"),
-		SiteLogo:            settings[SettingKeySiteLogo],
-		SiteSubtitle:        s.getStringOrDefault(settings, SettingKeySiteSubtitle, "Subscription to API Conversion Platform"),
-		APIBaseURL:          settings[SettingKeyAPIBaseURL],
-		ContactInfo:         settings[SettingKeyContactInfo],
-		DocURL:              settings[SettingKeyDocURL],
+		RegistrationEnabled:          settings[SettingKeyRegistrationEnabled] == "true",
+		EmailVerifyEnabled:           settings[SettingKeyEmailVerifyEnabled] == "true",
+		SMTPHost:                     settings[SettingKeySMTPHost],
+		SMTPUsername:                 settings[SettingKeySMTPUsername],
+		SMTPFrom:                     settings[SettingKeySMTPFrom],
+		SMTPFromName:                 settings[SettingKeySMTPFromName],
+		SMTPUseTLS:                   settings[SettingKeySMTPUseTLS] == "true",
+		SMTPPasswordConfigured:       settings[SettingKeySMTPPassword] != "",
+		TurnstileEnabled:             settings[SettingKeyTurnstileEnabled] == "true",
+		TurnstileSiteKey:             settings[SettingKeyTurnstileSiteKey],
+		TurnstileSecretKeyConfigured: settings[SettingKeyTurnstileSecretKey] != "",
+		SiteName:                     s.getStringOrDefault(settings, SettingKeySiteName, "Sub2API"),
+		SiteLogo:                     settings[SettingKeySiteLogo],
+		SiteSubtitle:                 s.getStringOrDefault(settings, SettingKeySiteSubtitle, "Subscription to API Conversion Platform"),
+		APIBaseURL:                   settings[SettingKeyAPIBaseURL],
+		ContactInfo:                  settings[SettingKeyContactInfo],
+		DocURL:                       settings[SettingKeyDocURL],
 	}

 	// 解析整数类型
--- a/backend/internal/service/settings_view.go
+++ b/backend/internal/service/settings_view.go
@@ -4,17 +4,19 @@ type SystemSettings struct {
 	RegistrationEnabled bool
 	EmailVerifyEnabled  bool

-	SMTPHost     string
-	SMTPPort     int
-	SMTPUsername string
-	SMTPPassword string
-	SMTPFrom     string
-	SMTPFromName string
-	SMTPUseTLS   bool
+	SMTPHost               string
+	SMTPPort               int
+	SMTPUsername           string
+	SMTPPassword           string
+	SMTPPasswordConfigured bool
+	SMTPFrom               string
+	SMTPFromName           string
+	SMTPUseTLS             bool

-	TurnstileEnabled   bool
-	TurnstileSiteKey   string
-	TurnstileSecretKey string
+	TurnstileEnabled             bool
+	TurnstileSiteKey             string
+	TurnstileSecretKey           string
+	TurnstileSecretKeyConfigured bool

 	SiteName     string
 	SiteLogo     string
--- a/backend/internal/setup/setup.go
+++ b/backend/internal/setup/setup.go
@@ -9,6 +9,7 @@ import (
 	"log"
 	"os"
 	"strconv"
+	"strings"
 	"time"

 	"github.com/Wei-Shaw/sub2api/internal/repository"
@@ -196,11 +197,17 @@ func Install(cfg *SetupConfig) error {

 	// Generate JWT secret if not provided
 	if cfg.JWT.Secret == "" {
+		if strings.EqualFold(cfg.Server.Mode, "release") {
+			return fmt.Errorf("jwt secret is required in release mode")
+		}
 		secret, err := generateSecret(32)
 		if err != nil {
 			return fmt.Errorf("failed to generate jwt secret: %w", err)
 		}
 		cfg.JWT.Secret = secret
+		log.Println("Warning: JWT secret auto-generated for non-release mode. Do not use in production.")
+	} else if strings.EqualFold(cfg.Server.Mode, "release") && len(cfg.JWT.Secret) < 32 {
+		return fmt.Errorf("jwt secret must be at least 32 characters in release mode")
 	}

 	// Test connections
@@ -474,12 +481,17 @@ func AutoSetupFromEnv() error {

 	// Generate JWT secret if not provided
 	if cfg.JWT.Secret == "" {
+		if strings.EqualFold(cfg.Server.Mode, "release") {
+			return fmt.Errorf("jwt secret is required in release mode")
+		}
 		secret, err := generateSecret(32)
 		if err != nil {
 			return fmt.Errorf("failed to generate jwt secret: %w", err)
 		}
 		cfg.JWT.Secret = secret
-		log.Println("Generated JWT secret automatically")
+		log.Println("Warning: JWT secret auto-generated for non-release mode. Do not use in production.")
+	} else if strings.EqualFold(cfg.Server.Mode, "release") && len(cfg.JWT.Secret) < 32 {
+		return fmt.Errorf("jwt secret must be at least 32 characters in release mode")
 	}

 	// Generate admin password if not provided
@@ -489,8 +501,8 @@ func AutoSetupFromEnv() error {
 			return fmt.Errorf("failed to generate admin password: %w", err)
 		}
 		cfg.Admin.Password = password
-		log.Printf("Generated admin password: %s", cfg.Admin.Password)
-		log.Println("IMPORTANT: Save this password! It will not be shown again.")
+		fmt.Printf("Generated admin password (one-time): %s\n", cfg.Admin.Password)
+		fmt.Println("IMPORTANT: Save this password! It will not be shown again.")
 	}

 	// Test database connection
--- a/backend/internal/util/logredact/redact.go
+++ b/backend/internal/util/logredact/redact.go
@@ -0,0 +1,100 @@
+package logredact
+
+import (
+	"encoding/json"
+	"strings"
+)
+
+// maxRedactDepth 限制递归深度以防止栈溢出
+const maxRedactDepth = 32
+
+var defaultSensitiveKeys = map[string]struct{}{
+	"authorization_code": {},
+	"code":               {},
+	"code_verifier":      {},
+	"access_token":       {},
+	"refresh_token":      {},
+	"id_token":           {},
+	"client_secret":      {},
+	"password":           {},
+}
+
+func RedactMap(input map[string]any, extraKeys ...string) map[string]any {
+	if input == nil {
+		return map[string]any{}
+	}
+	keys := buildKeySet(extraKeys)
+	redacted, ok := redactValueWithDepth(input, keys, 0).(map[string]any)
+	if !ok {
+		return map[string]any{}
+	}
+	return redacted
+}
+
+func RedactJSON(raw []byte, extraKeys ...string) string {
+	if len(raw) == 0 {
+		return ""
+	}
+	var value any
+	if err := json.Unmarshal(raw, &value); err != nil {
+		return "<non-json payload redacted>"
+	}
+	keys := buildKeySet(extraKeys)
+	redacted := redactValueWithDepth(value, keys, 0)
+	encoded, err := json.Marshal(redacted)
+	if err != nil {
+		return "<redacted>"
+	}
+	return string(encoded)
+}
+
+func buildKeySet(extraKeys []string) map[string]struct{} {
+	keys := make(map[string]struct{}, len(defaultSensitiveKeys)+len(extraKeys))
+	for k := range defaultSensitiveKeys {
+		keys[k] = struct{}{}
+	}
+	for _, key := range extraKeys {
+		normalized := normalizeKey(key)
+		if normalized == "" {
+			continue
+		}
+		keys[normalized] = struct{}{}
+	}
+	return keys
+}
+
+func redactValueWithDepth(value any, keys map[string]struct{}, depth int) any {
+	if depth > maxRedactDepth {
+		return "<depth limit exceeded>"
+	}
+
+	switch v := value.(type) {
+	case map[string]any:
+		out := make(map[string]any, len(v))
+		for k, val := range v {
+			if isSensitiveKey(k, keys) {
+				out[k] = "***"
+				continue
+			}
+			out[k] = redactValueWithDepth(val, keys, depth+1)
+		}
+		return out
+	case []any:
+		out := make([]any, len(v))
+		for i, item := range v {
+			out[i] = redactValueWithDepth(item, keys, depth+1)
+		}
+		return out
+	default:
+		return value
+	}
+}
+
+func isSensitiveKey(key string, keys map[string]struct{}) bool {
+	_, ok := keys[normalizeKey(key)]
+	return ok
+}
+
+func normalizeKey(key string) string {
+	return strings.ToLower(strings.TrimSpace(key))
+}
--- a/backend/internal/util/responseheaders/responseheaders.go
+++ b/backend/internal/util/responseheaders/responseheaders.go
@@ -0,0 +1,93 @@
+package responseheaders
+
+import (
+	"net/http"
+	"strings"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+)
+
+// defaultAllowed 定义允许透传的响应头白名单
+// 注意：以下头部由 Go HTTP 包自动处理，不应手动设置：
+//   - content-length: 由 ResponseWriter 根据实际写入数据自动设置
+//   - transfer-encoding: 由 HTTP 库根据需要自动添加/移除
+//   - connection: 由 HTTP 库管理连接复用
+var defaultAllowed = map[string]struct{}{
+	"content-type":                   {},
+	"content-encoding":               {},
+	"content-language":               {},
+	"cache-control":                  {},
+	"etag":                           {},
+	"last-modified":                  {},
+	"expires":                        {},
+	"vary":                           {},
+	"date":                           {},
+	"x-request-id":                   {},
+	"x-ratelimit-limit-requests":     {},
+	"x-ratelimit-limit-tokens":       {},
+	"x-ratelimit-remaining-requests": {},
+	"x-ratelimit-remaining-tokens":   {},
+	"x-ratelimit-reset-requests":     {},
+	"x-ratelimit-reset-tokens":       {},
+	"retry-after":                    {},
+	"location":                       {},
+	"www-authenticate":               {},
+}
+
+// hopByHopHeaders 是跳过的 hop-by-hop 头部，这些头部由 HTTP 库自动处理
+var hopByHopHeaders = map[string]struct{}{
+	"content-length":    {},
+	"transfer-encoding": {},
+	"connection":        {},
+}
+
+func FilterHeaders(src http.Header, cfg config.ResponseHeaderConfig) http.Header {
+	allowed := make(map[string]struct{}, len(defaultAllowed)+len(cfg.AdditionalAllowed))
+	for key := range defaultAllowed {
+		allowed[key] = struct{}{}
+	}
+	for _, key := range cfg.AdditionalAllowed {
+		normalized := strings.ToLower(strings.TrimSpace(key))
+		if normalized == "" {
+			continue
+		}
+		allowed[normalized] = struct{}{}
+	}
+
+	forceRemove := make(map[string]struct{}, len(cfg.ForceRemove))
+	for _, key := range cfg.ForceRemove {
+		normalized := strings.ToLower(strings.TrimSpace(key))
+		if normalized == "" {
+			continue
+		}
+		forceRemove[normalized] = struct{}{}
+	}
+
+	filtered := make(http.Header, len(src))
+	for key, values := range src {
+		lower := strings.ToLower(key)
+		if _, blocked := forceRemove[lower]; blocked {
+			continue
+		}
+		if _, ok := allowed[lower]; !ok {
+			continue
+		}
+		// 跳过 hop-by-hop 头部，这些由 HTTP 库自动处理
+		if _, isHopByHop := hopByHopHeaders[lower]; isHopByHop {
+			continue
+		}
+		for _, value := range values {
+			filtered.Add(key, value)
+		}
+	}
+	return filtered
+}
+
+func WriteFilteredHeaders(dst http.Header, src http.Header, cfg config.ResponseHeaderConfig) {
+	filtered := FilterHeaders(src, cfg)
+	for key, values := range filtered {
+		for _, value := range values {
+			dst.Add(key, value)
+		}
+	}
+}
--- a/backend/internal/util/urlvalidator/validator.go
+++ b/backend/internal/util/urlvalidator/validator.go
@@ -0,0 +1,121 @@
+package urlvalidator
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net"
+	"net/url"
+	"strings"
+	"time"
+)
+
+type ValidationOptions struct {
+	AllowedHosts     []string
+	RequireAllowlist bool
+	AllowPrivate     bool
+}
+
+func ValidateHTTPSURL(raw string, opts ValidationOptions) (string, error) {
+	trimmed := strings.TrimSpace(raw)
+	if trimmed == "" {
+		return "", errors.New("url is required")
+	}
+
+	parsed, err := url.Parse(trimmed)
+	if err != nil || parsed.Scheme == "" || parsed.Host == "" {
+		return "", fmt.Errorf("invalid url: %s", trimmed)
+	}
+	if !strings.EqualFold(parsed.Scheme, "https") {
+		return "", fmt.Errorf("invalid url scheme: %s", parsed.Scheme)
+	}
+
+	host := strings.ToLower(strings.TrimSpace(parsed.Hostname()))
+	if host == "" {
+		return "", errors.New("invalid host")
+	}
+	if !opts.AllowPrivate && isBlockedHost(host) {
+		return "", fmt.Errorf("host is not allowed: %s", host)
+	}
+
+	allowlist := normalizeAllowlist(opts.AllowedHosts)
+	if opts.RequireAllowlist && len(allowlist) == 0 {
+		return "", errors.New("allowlist is not configured")
+	}
+	if len(allowlist) > 0 && !isAllowedHost(host, allowlist) {
+		return "", fmt.Errorf("host is not allowed: %s", host)
+	}
+
+	parsed.Path = strings.TrimRight(parsed.Path, "/")
+	parsed.RawPath = ""
+	return strings.TrimRight(parsed.String(), "/"), nil
+}
+
+// ValidateResolvedIP 验证 DNS 解析后的 IP 地址是否安全
+// 用于防止 DNS Rebinding 攻击：在实际 HTTP 请求时调用此函数验证解析后的 IP
+func ValidateResolvedIP(host string) error {
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	ips, err := net.DefaultResolver.LookupIP(ctx, "ip", host)
+	if err != nil {
+		return fmt.Errorf("dns resolution failed: %w", err)
+	}
+
+	for _, ip := range ips {
+		if ip.IsLoopback() || ip.IsPrivate() || ip.IsLinkLocalUnicast() ||
+			ip.IsLinkLocalMulticast() || ip.IsUnspecified() {
+			return fmt.Errorf("resolved ip %s is not allowed", ip.String())
+		}
+	}
+	return nil
+}
+
+func normalizeAllowlist(values []string) []string {
+	if len(values) == 0 {
+		return nil
+	}
+	normalized := make([]string, 0, len(values))
+	for _, v := range values {
+		entry := strings.ToLower(strings.TrimSpace(v))
+		if entry == "" {
+			continue
+		}
+		if host, _, err := net.SplitHostPort(entry); err == nil {
+			entry = host
+		}
+		normalized = append(normalized, entry)
+	}
+	return normalized
+}
+
+func isAllowedHost(host string, allowlist []string) bool {
+	for _, entry := range allowlist {
+		if entry == "" {
+			continue
+		}
+		if strings.HasPrefix(entry, "*.") {
+			suffix := strings.TrimPrefix(entry, "*.")
+			if host == suffix || strings.HasSuffix(host, "."+suffix) {
+				return true
+			}
+			continue
+		}
+		if host == entry {
+			return true
+		}
+	}
+	return false
+}
+
+func isBlockedHost(host string) bool {
+	if host == "localhost" || strings.HasSuffix(host, ".localhost") {
+		return true
+	}
+	if ip := net.ParseIP(host); ip != nil {
+		if ip.IsLoopback() || ip.IsPrivate() || ip.IsLinkLocalUnicast() || ip.IsLinkLocalMulticast() || ip.IsUnspecified() {
+			return true
+		}
+	}
+	return false
+}
--- a/deploy/Caddyfile
+++ b/deploy/Caddyfile
@@ -25,8 +25,8 @@
 		timeouts {
 			read_body 30s
 			read_header 10s
-			write 60s
-			idle 120s
+			write 300s
+			idle 300s
 		}
 	}
 }
@@ -77,7 +77,10 @@ example.com {
 			write_buffer 16KB
 			compression off
 		}
-		
+
+		# SSE/流式传输优化：禁用响应缓冲，立即刷新数据给客户端
+		flush_interval -1
+
 		# 故障转移
 		fail_duration 30s
 		max_fails 3
@@ -92,6 +95,10 @@ example.com {
 		gzip 6
 		minimum_length 256
 		match {
+			# SSE 请求通常会带 Accept: text/event-stream，需排除压缩
+			not header Accept text/event-stream*
+			# 排除已知 SSE 路径（即便 Accept 缺失）
+			not path /v1/messages /v1/responses /responses /antigravity/v1/messages /v1beta/models/* /antigravity/v1beta/models/*
 			header Content-Type text/*
 			header Content-Type application/json*
 			header Content-Type application/javascript*
@@ -179,6 +186,3 @@ example.com {
 # =============================================================================
 # HTTP 重定向到 HTTPS (Caddy 默认自动处理，此处显式声明)
 # =============================================================================
-; http://example.com {
-; 	redir https://{host}{uri} permanent
-; }
--- a/deploy/config.example.yaml
+++ b/deploy/config.example.yaml
@@ -12,6 +12,8 @@ server:
  port: 8080
  # Mode: "debug" for development, "release" for production
  mode: "release"
+  # Trusted proxies for X-Forwarded-For parsing (CIDR/IP). Empty disables trusted proxies.
+  trusted_proxies: []

 # =============================================================================
 # Run Mode Configuration
@@ -21,12 +23,54 @@ server:
 # - simple: Hides SaaS features and skips billing/balance checks
 run_mode: "standard"

+# =============================================================================
+# CORS Configuration
+# =============================================================================
+cors:
+  # Allowed origins list. Leave empty to disable cross-origin requests.
+  allowed_origins: []
+  # Allow credentials (cookies/authorization headers). Cannot be used with "*".
+  allow_credentials: true
+
+# =============================================================================
+# Security Configuration
+# =============================================================================
+security:
+  url_allowlist:
+    # Allowed upstream hosts for API proxying
+    upstream_hosts:
+      - "api.openai.com"
+      - "api.anthropic.com"
+      - "generativelanguage.googleapis.com"
+      - "cloudcode-pa.googleapis.com"
+      - "*.openai.azure.com"
+    # Allowed hosts for pricing data download
+    pricing_hosts:
+      - "raw.githubusercontent.com"
+    # Allowed hosts for CRS sync (required when using CRS sync)
+    crs_hosts: []
+    # Allow localhost/private IPs for upstream/pricing/CRS (use only in trusted networks)
+    allow_private_hosts: false
+  response_headers:
+    # Extra allowed response headers from upstream
+    additional_allowed: []
+    # Force-remove response headers from upstream
+    force_remove: []
+  csp:
+    # Enable Content-Security-Policy header
+    enabled: true
+    # Default CSP policy (override if you host assets on other domains)
+    policy: "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data: https:; font-src 'self' data:; connect-src 'self' https:; frame-ancestors 'none'; base-uri 'self'; form-action 'self'"
+  proxy_probe:
+    # Allow skipping TLS verification for proxy probe (debug only)
+    insecure_skip_verify: false
+
 # =============================================================================
 # 网关配置
 # =============================================================================
 gateway:
  # 等待上游响应头超时时间（秒）
-  response_header_timeout: 300
+  response_header_timeout: 600
  # 请求体最大字节数（默认 100MB）
  max_body_size: 104857600
  # 连接池隔离策略：
@@ -38,14 +82,35 @@ gateway:
  max_idle_conns: 240
  max_idle_conns_per_host: 120
  max_conns_per_host: 240
-  idle_conn_timeout_seconds: 300
+  idle_conn_timeout_seconds: 90
  # 上游连接池客户端缓存配置
  # max_upstream_clients: 最大缓存客户端数量，超出后淘汰最久未使用的
  # client_idle_ttl_seconds: 客户端空闲回收阈值（秒），超时且无活跃请求时回收
  max_upstream_clients: 5000
  client_idle_ttl_seconds: 900
  # 并发槽位过期时间（分钟）
-  concurrency_slot_ttl_minutes: 15
+  concurrency_slot_ttl_minutes: 30
+  # 流数据间隔超时（秒），0=禁用
+  stream_data_interval_timeout: 180
+  # 流式 keepalive 间隔（秒），0=禁用
+  stream_keepalive_interval: 10
+  # SSE 单行最大字节数（默认 10MB）
+  max_line_size: 10485760
+  # Log upstream error response body summary (safe/truncated; does not log request content)
+  log_upstream_error_body: false
+  # Max bytes to log from upstream error body
+  log_upstream_error_body_max_bytes: 2048
+  # Auto inject anthropic-beta for API-key accounts when needed (default off)
+  inject_beta_for_apikey: false
+  # Allow failover on selected 400 errors (default off)
+  failover_on_400: false
+
+# =============================================================================
+# 并发等待配置
+# =============================================================================
+concurrency:
+  # 并发等待期间的 SSE ping 间隔（秒）
+  ping_interval: 10

 # =============================================================================
 # Database Configuration (PostgreSQL)
@@ -77,7 +142,7 @@ jwt:
  # IMPORTANT: Change this to a random string in production!
  # Generate with: openssl rand -hex 32
  secret: "change-this-to-a-secure-random-string"
-  # Token expiration time in hours
+  # Token expiration time in hours (max 24)
  expire_hour: 24

 # =============================================================================
@@ -123,19 +188,21 @@ pricing:
  hash_check_interval_minutes: 10

 # =============================================================================
-# Gateway (Optional)
+# Billing Configuration
 # =============================================================================
-gateway:
-  # Wait time (in seconds) for upstream response headers (streaming body not affected)
-  response_header_timeout: 300
-  # Log upstream error response body summary (safe/truncated; does not log request content)
-  log_upstream_error_body: false
-  # Max bytes to log from upstream error body
-  log_upstream_error_body_max_bytes: 2048
-  # Auto inject anthropic-beta for API-key accounts when needed (default off)
-  inject_beta_for_apikey: false
-  # Allow failover on selected 400 errors (default off)
-  failover_on_400: false
+billing:
+  circuit_breaker:
+    enabled: true
+    failure_threshold: 5
+    reset_timeout_seconds: 30
+    half_open_requests: 3
+
+# =============================================================================
+# Turnstile Configuration
+# =============================================================================
+turnstile:
+  # Require Turnstile in release mode (when enabled, login/register will fail if not configured)
+  required: false

 # =============================================================================
 # Gemini OAuth (Required for Gemini accounts)
--- a/frontend/src/api/admin/settings.ts
+++ b/frontend/src/api/admin/settings.ts
@@ -26,14 +26,37 @@ export interface SystemSettings {
  smtp_host: string
  smtp_port: number
  smtp_username: string
-  smtp_password: string
+  smtp_password_configured: boolean
  smtp_from_email: string
  smtp_from_name: string
  smtp_use_tls: boolean
  // Cloudflare Turnstile settings
  turnstile_enabled: boolean
  turnstile_site_key: string
-  turnstile_secret_key: string
+  turnstile_secret_key_configured: boolean
+}
+
+export interface UpdateSettingsRequest {
+  registration_enabled?: boolean
+  email_verify_enabled?: boolean
+  default_balance?: number
+  default_concurrency?: number
+  site_name?: string
+  site_logo?: string
+  site_subtitle?: string
+  api_base_url?: string
+  contact_info?: string
+  doc_url?: string
+  smtp_host?: string
+  smtp_port?: number
+  smtp_username?: string
+  smtp_password?: string
+  smtp_from_email?: string
+  smtp_from_name?: string
+  smtp_use_tls?: boolean
+  turnstile_enabled?: boolean
+  turnstile_site_key?: string
+  turnstile_secret_key?: string
 }

 /**
@@ -50,7 +73,7 @@ export async function getSettings(): Promise<SystemSettings> {
 * @param settings - Partial settings to update
 * @returns Updated settings
 */
-export async function updateSettings(settings: Partial<SystemSettings>): Promise<SystemSettings> {
+export async function updateSettings(settings: UpdateSettingsRequest): Promise<SystemSettings> {
  const { data } = await apiClient.put<SystemSettings>('/admin/settings', settings)
  return data
 }
--- a/frontend/src/api/client.ts
+++ b/frontend/src/api/client.ts
@@ -62,8 +62,24 @@ apiClient.interceptors.response.use(

      // 401: Unauthorized - clear token and redirect to login
      if (status === 401) {
+        const hasToken = !!localStorage.getItem('auth_token')
+        const url = error.config?.url || ''
+        const isAuthEndpoint =
+          url.includes('/auth/login') || url.includes('/auth/register') || url.includes('/auth/refresh')
+        const headers = error.config?.headers as Record<string, unknown> | undefined
+        const authHeader = headers?.Authorization ?? headers?.authorization
+        const sentAuth =
+          typeof authHeader === 'string'
+            ? authHeader.trim() !== ''
+            : Array.isArray(authHeader)
+            ? authHeader.length > 0
+            : !!authHeader
+
        localStorage.removeItem('auth_token')
        localStorage.removeItem('auth_user')
+        if ((hasToken || sentAuth) && !isAuthEndpoint) {
+          sessionStorage.setItem('auth_expired', '1')
+        }
        // Only redirect if not already on login page
        if (!window.location.pathname.includes('/login')) {
          window.location.href = '/login'
--- a/frontend/src/components/account/OAuthAuthorizationFlow.vue
+++ b/frontend/src/components/account/OAuthAuthorizationFlow.vue
@@ -136,16 +136,16 @@
              <ol
                class="list-inside list-decimal space-y-1 text-xs text-amber-700 dark:text-amber-300"
              >
-                <li v-html="t('admin.accounts.oauth.step1')"></li>
-                <li v-html="t('admin.accounts.oauth.step2')"></li>
-                <li v-html="t('admin.accounts.oauth.step3')"></li>
-                <li v-html="t('admin.accounts.oauth.step4')"></li>
-                <li v-html="t('admin.accounts.oauth.step5')"></li>
-                <li v-html="t('admin.accounts.oauth.step6')"></li>
+                <li>{{ t('admin.accounts.oauth.step1') }}</li>
+                <li>{{ t('admin.accounts.oauth.step2') }}</li>
+                <li>{{ t('admin.accounts.oauth.step3') }}</li>
+                <li>{{ t('admin.accounts.oauth.step4') }}</li>
+                <li>{{ t('admin.accounts.oauth.step5') }}</li>
+                <li>{{ t('admin.accounts.oauth.step6') }}</li>
              </ol>
              <p
                class="mt-2 text-xs text-amber-600 dark:text-amber-400"
-                v-html="t('admin.accounts.oauth.sessionKeyFormat')"
+                v-text="t('admin.accounts.oauth.sessionKeyFormat')"
              ></p>
            </div>

@@ -390,7 +390,7 @@
                >
                  <p
                    class="text-xs text-amber-800 dark:text-amber-300"
-                    v-html="oauthImportantNotice"
+                    v-text="oauthImportantNotice"
                  ></p>
                </div>
                <!-- Proxy Warning (for non-OpenAI) -->
@@ -400,7 +400,7 @@
                >
                  <p
                    class="text-xs text-yellow-800 dark:text-yellow-300"
-                    v-html="t('admin.accounts.oauth.proxyWarning')"
+                    v-text="t('admin.accounts.oauth.proxyWarning')"
                  ></p>
                </div>
              </div>
@@ -423,7 +423,7 @@
                </p>
                <p
                  class="mb-3 text-sm text-blue-700 dark:text-blue-300"
-                  v-html="oauthAuthCodeDesc"
+                  v-text="oauthAuthCodeDesc"
                ></p>
                <div>
                  <label class="input-label">
--- a/frontend/src/components/keys/UseKeyModal.vue
+++ b/frontend/src/components/keys/UseKeyModal.vue
@@ -107,7 +107,10 @@
                </button>
              </div>
              <!-- Code Content -->
-              <pre class="p-4 text-sm font-mono text-gray-100 overflow-x-auto"><code v-html="file.highlighted"></code></pre>
+              <pre class="p-4 text-sm font-mono text-gray-100 overflow-x-auto">
+                <code v-if="file.highlighted" v-html="file.highlighted"></code>
+                <code v-else v-text="file.content"></code>
+              </pre>
            </div>
          </div>
        </div>
@@ -164,8 +167,8 @@ interface TabConfig {
 interface FileConfig {
  path: string
  content: string
-  highlighted: string
  hint?: string  // Optional hint message for this file
+  highlighted?: string
 }

 const props = defineProps<Props>()
@@ -311,14 +314,23 @@ const platformNote = computed(() => {
  }
 })

-// Syntax highlighting helpers
-const keyword = (text: string) => `<span class="text-purple-400">${text}</span>`
-const variable = (text: string) => `<span class="text-cyan-400">${text}</span>`
-const string = (text: string) => `<span class="text-green-400">${text}</span>`
-const operator = (text: string) => `<span class="text-yellow-400">${text}</span>`
-const comment = (text: string) => `<span class="text-gray-500">${text}</span>`
-const key = (text: string) => `<span class="text-blue-400">${text}</span>`
+const escapeHtml = (value: string) => value
+  .replace(/&/g, '&amp;')
+  .replace(/</g, '&lt;')
+  .replace(/>/g, '&gt;')
+  .replace(/"/g, '&quot;')
+  .replace(/'/g, '&#39;')

+const wrapToken = (className: string, value: string) =>
+  `<span class="${className}">${escapeHtml(value)}</span>`
+
+const keyword = (value: string) => wrapToken('text-emerald-300', value)
+const variable = (value: string) => wrapToken('text-sky-200', value)
+const operator = (value: string) => wrapToken('text-slate-400', value)
+const string = (value: string) => wrapToken('text-amber-200', value)
+const comment = (value: string) => wrapToken('text-slate-500', value)
+
+// Syntax highlighting helpers
 // Generate file configs based on platform and active tab
 const currentFiles = computed((): FileConfig[] => {
  const baseUrl = props.baseUrl || window.location.origin
@@ -343,37 +355,29 @@ const currentFiles = computed((): FileConfig[] => {
 function generateAnthropicFiles(baseUrl: string, apiKey: string): FileConfig[] {
  let path: string
  let content: string
-  let highlighted: string

  switch (activeTab.value) {
    case 'unix':
      path = 'Terminal'
      content = `export ANTHROPIC_BASE_URL="${baseUrl}"
 export ANTHROPIC_AUTH_TOKEN="${apiKey}"`
-      highlighted = `${keyword('export')} ${variable('ANTHROPIC_BASE_URL')}${operator('=')}${string(`"${baseUrl}"`)}
-${keyword('export')} ${variable('ANTHROPIC_AUTH_TOKEN')}${operator('=')}${string(`"${apiKey}"`)}`
      break
    case 'cmd':
      path = 'Command Prompt'
      content = `set ANTHROPIC_BASE_URL=${baseUrl}
 set ANTHROPIC_AUTH_TOKEN=${apiKey}`
-      highlighted = `${keyword('set')} ${variable('ANTHROPIC_BASE_URL')}${operator('=')}${baseUrl}
-${keyword('set')} ${variable('ANTHROPIC_AUTH_TOKEN')}${operator('=')}${apiKey}`
      break
    case 'powershell':
      path = 'PowerShell'
      content = `$env:ANTHROPIC_BASE_URL="${baseUrl}"
 $env:ANTHROPIC_AUTH_TOKEN="${apiKey}"`
-      highlighted = `${keyword('$env:')}${variable('ANTHROPIC_BASE_URL')}${operator('=')}${string(`"${baseUrl}"`)}
-${keyword('$env:')}${variable('ANTHROPIC_AUTH_TOKEN')}${operator('=')}${string(`"${apiKey}"`)}`
      break
    default:
      path = 'Terminal'
      content = ''
-      highlighted = ''
  }

-  return [{ path, content, highlighted }]
+  return [{ path, content }]
 }

 function generateGeminiCliContent(baseUrl: string, apiKey: string): FileConfig {
@@ -398,9 +402,9 @@ ${keyword('export')} ${variable('GEMINI_MODEL')}${operator('=')}${string(`"${mod
      content = `set GOOGLE_GEMINI_BASE_URL=${baseUrl}
 set GEMINI_API_KEY=${apiKey}
 set GEMINI_MODEL=${model}`
-      highlighted = `${keyword('set')} ${variable('GOOGLE_GEMINI_BASE_URL')}${operator('=')}${baseUrl}
-${keyword('set')} ${variable('GEMINI_API_KEY')}${operator('=')}${apiKey}
-${keyword('set')} ${variable('GEMINI_MODEL')}${operator('=')}${model}
+      highlighted = `${keyword('set')} ${variable('GOOGLE_GEMINI_BASE_URL')}${operator('=')}${string(baseUrl)}
+${keyword('set')} ${variable('GEMINI_API_KEY')}${operator('=')}${string(apiKey)}
+${keyword('set')} ${variable('GEMINI_MODEL')}${operator('=')}${string(model)}
 ${comment(`REM ${modelComment}`)}`
      break
    case 'powershell':
@@ -440,40 +444,20 @@ base_url = "${baseUrl}"
 wire_api = "responses"
 requires_openai_auth = true`

-  const configHighlighted = `${key('model_provider')} ${operator('=')} ${string('"sub2api"')}
-${key('model')} ${operator('=')} ${string('"gpt-5.2-codex"')}
-${key('model_reasoning_effort')} ${operator('=')} ${string('"high"')}
-${key('network_access')} ${operator('=')} ${string('"enabled"')}
-${key('disable_response_storage')} ${operator('=')} ${keyword('true')}
-${key('windows_wsl_setup_acknowledged')} ${operator('=')} ${keyword('true')}
-${key('model_verbosity')} ${operator('=')} ${string('"high"')}
-
-${comment('[model_providers.sub2api]')}
-${key('name')} ${operator('=')} ${string('"sub2api"')}
-${key('base_url')} ${operator('=')} ${string(`"${baseUrl}"`)}
-${key('wire_api')} ${operator('=')} ${string('"responses"')}
-${key('requires_openai_auth')} ${operator('=')} ${keyword('true')}`
-
  // auth.json content
  const authContent = `{
  "OPENAI_API_KEY": "${apiKey}"
 }`

-  const authHighlighted = `{
-  ${key('"OPENAI_API_KEY"')}: ${string(`"${apiKey}"`)}
-}`
-
  return [
    {
      path: `${configDir}/config.toml`,
      content: configContent,
-      highlighted: configHighlighted,
      hint: t('keys.useKeyModal.openai.configTomlHint')
    },
    {
      path: `${configDir}/auth.json`,
-      content: authContent,
-      highlighted: authHighlighted
+      content: authContent
    }
  ]
 }
--- a/frontend/src/components/layout/AuthLayout.vue
+++ b/frontend/src/components/layout/AuthLayout.vue
@@ -63,6 +63,7 @@
 <script setup lang="ts">
 import { ref, computed, onMounted } from 'vue'
 import { getPublicSettings } from '@/api/auth'
+import { sanitizeUrl } from '@/utils/url'

 const siteName = ref('Sub2API')
 const siteLogo = ref('')
@@ -74,7 +75,7 @@ onMounted(async () => {
  try {
    const settings = await getPublicSettings()
    siteName.value = settings.site_name || 'Sub2API'
-    siteLogo.value = settings.site_logo || ''
+    siteLogo.value = sanitizeUrl(settings.site_logo || '', { allowRelative: true })
    siteSubtitle.value = settings.site_subtitle || 'Subscription to API Conversion Platform'
  } catch (error) {
    console.error('Failed to load public settings:', error)
--- a/frontend/src/i18n/locales/en.ts
+++ b/frontend/src/i18n/locales/en.ts
@@ -200,6 +200,7 @@ export default {
    registrationFailed: 'Registration failed. Please try again.',
    loginSuccess: 'Login successful! Welcome back.',
    accountCreatedSuccess: 'Account created successfully! Welcome to {siteName}.',
+    reloginRequired: 'Session expired. Please log in again.',
    turnstileExpired: 'Verification expired, please try again',
    turnstileFailed: 'Verification failed, please try again',
    completeVerification: 'Please complete the verification',
@@ -1127,13 +1128,13 @@ export default {
          'One sessionKey per line, e.g.:\nsk-ant-sid01-xxxxx...\nsk-ant-sid01-yyyyy...',
        sessionKeyPlaceholderSingle: 'sk-ant-sid01-xxxxx...',
        howToGetSessionKey: 'How to get sessionKey',
-        step1: 'Login to <strong>claude.ai</strong> in your browser',
-        step2: 'Press <kbd>F12</kbd> to open Developer Tools',
-        step3: 'Go to <strong>Application</strong> tab',
-        step4: 'Find <strong>Cookies</strong> → <strong>https://claude.ai</strong>',
-        step5: 'Find the row with key <strong>sessionKey</strong>',
-        step6: 'Copy the <strong>Value</strong>',
-        sessionKeyFormat: 'sessionKey usually starts with <code>sk-ant-sid01-</code>',
+        step1: 'Login to claude.ai in your browser',
+        step2: 'Press F12 to open Developer Tools',
+        step3: 'Go to Application tab',
+        step4: 'Find Cookies → https://claude.ai',
+        step5: 'Find the row with key sessionKey',
+        step6: 'Copy the Value',
+        sessionKeyFormat: 'sessionKey usually starts with sk-ant-sid01-',
        startAutoAuth: 'Start Auto-Auth',
        authorizing: 'Authorizing...',
        followSteps: 'Follow these steps to authorize your Claude account:',
@@ -1145,10 +1146,10 @@ export default {
        openUrlDesc:
          'Open the authorization URL in a new tab, log in to your Claude account and authorize.',
        proxyWarning:
-          '<strong>Note:</strong> If you configured a proxy, make sure your browser uses the same proxy to access the authorization page.',
+          'Note: If you configured a proxy, make sure your browser uses the same proxy to access the authorization page.',
        step3EnterCode: 'Enter the Authorization Code',
        authCodeDesc:
-          'After authorization is complete, the page will display an <strong>Authorization Code</strong>. Copy and paste it below:',
+          'After authorization is complete, the page will display an Authorization Code. Copy and paste it below:',
        authCode: 'Authorization Code',
        authCodePlaceholder: 'Paste the Authorization Code from Claude page...',
        authCodeHint: 'Paste the Authorization Code copied from the Claude page',
@@ -1169,10 +1170,10 @@ export default {
          openUrlDesc:
            'Open the authorization URL in a new tab, log in to your OpenAI account and authorize.',
          importantNotice:
-            '<strong>Important:</strong> The page may take a while to load after authorization. Please wait patiently. When the browser address bar changes to <code>http://localhost...</code>, the authorization is complete.',
+            'Important: The page may take a while to load after authorization. Please wait patiently. When the browser address bar changes to http://localhost..., the authorization is complete.',
          step3EnterCode: 'Enter Authorization URL or Code',
          authCodeDesc:
-            'After authorization is complete, when the page URL becomes <code>http://localhost:xxx/auth/callback?code=...</code>:',
+            'After authorization is complete, when the page URL becomes http://localhost:xxx/auth/callback?code=...:',
          authCode: 'Authorization URL or Code',
          authCodePlaceholder:
            'Option 1: Copy the complete URL\n(http://localhost:xxx/auth/callback?code=...)\nOption 2: Copy only the code parameter value',
@@ -1195,7 +1196,7 @@ export default {
 	            'Open the authorization URL in a new tab, log in to your Google account and authorize.',
 	          step3EnterCode: 'Enter Authorization URL or Code',
 	          authCodeDesc:
-	            'After authorization, copy the callback URL (recommended) or just the <code>code</code> and paste it below.',
+	            'After authorization, copy the callback URL (recommended) or just the code and paste it below.',
 	          authCode: 'Callback URL or Code',
 	          authCodePlaceholder:
 	            'Option 1 (recommended): Paste the callback URL\nOption 2: Paste only the code value',
@@ -1237,10 +1238,10 @@ export default {
          step2OpenUrl: 'Open the URL in your browser and complete authorization',
          openUrlDesc: 'Open the authorization URL in a new tab, log in to your Google account and authorize.',
          importantNotice:
-            '<strong>Important:</strong> The page may take a while to load after authorization. Please wait patiently. When the browser address bar shows <code>http://localhost...</code>, authorization is complete.',
+            'Important: The page may take a while to load after authorization. Please wait patiently. When the browser address bar shows http://localhost..., authorization is complete.',
          step3EnterCode: 'Enter Authorization URL or Code',
          authCodeDesc:
-            'After authorization, when the page URL becomes <code>http://localhost:xxx/auth/callback?code=...</code>:',
+            'After authorization, when the page URL becomes http://localhost:xxx/auth/callback?code=...:',
          authCode: 'Authorization URL or Code',
          authCodePlaceholder:
            'Option 1: Copy the complete URL\n(http://localhost:xxx/auth/callback?code=...)\nOption 2: Copy only the code parameter value',
@@ -1652,8 +1653,8 @@ export default {
        secretKey: 'Secret Key',
        siteKeyHint: 'Get this from your Cloudflare Dashboard',
        cloudflareDashboard: 'Cloudflare Dashboard',
-        secretKeyHint: 'Server-side verification key (keep this secret)'
-      },
+        secretKeyHint: 'Server-side verification key (keep this secret)',
+        secretKeyConfiguredHint: 'Secret key configured. Leave empty to keep the current value.'      },
      defaults: {
        title: 'Default User Settings',
        description: 'Default values for new users',
@@ -1703,6 +1704,8 @@ export default {
        password: 'SMTP Password',
        passwordPlaceholder: '********',
        passwordHint: 'Leave empty to keep existing password',
+        passwordConfiguredPlaceholder: '********',
+        passwordConfiguredHint: 'Password configured. Leave empty to keep the current value.',
        fromEmail: 'From Email',
        fromEmailPlaceholder: "noreply{'@'}example.com",
        fromName: 'From Name',
--- a/frontend/src/i18n/locales/zh.ts
+++ b/frontend/src/i18n/locales/zh.ts
@@ -197,6 +197,7 @@ export default {
    registrationFailed: '注册失败，请重试。',
    loginSuccess: '登录成功！欢迎回来。',
    accountCreatedSuccess: '账户创建成功！欢迎使用 {siteName}。',
+    reloginRequired: '会话已过期，请重新登录。',
    turnstileExpired: '验证已过期，请重试',
    turnstileFailed: '验证失败，请重试',
    completeVerification: '请完成验证',
@@ -1279,13 +1280,13 @@ export default {
          '每行一个 sessionKey，例如：\nsk-ant-sid01-xxxxx...\nsk-ant-sid01-yyyyy...',
        sessionKeyPlaceholderSingle: 'sk-ant-sid01-xxxxx...',
        howToGetSessionKey: '如何获取 sessionKey',
-        step1: '在浏览器中登录 <strong>claude.ai</strong>',
-        step2: '按 <kbd>F12</kbd> 打开开发者工具',
-        step3: '切换到 <strong>Application</strong> 标签',
-        step4: '找到 <strong>Cookies</strong> → <strong>https://claude.ai</strong>',
-        step5: '找到 <strong>sessionKey</strong> 所在行',
-        step6: '复制 <strong>Value</strong> 列的值',
-        sessionKeyFormat: 'sessionKey 通常以 <code>sk-ant-sid01-</code> 开头',
+        step1: '在浏览器中登录 claude.ai',
+        step2: '按 F12 打开开发者工具',
+        step3: '切换到 Application 标签',
+        step4: '找到 Cookies → https://claude.ai',
+        step5: '找到 sessionKey 所在行',
+        step6: '复制 Value 列的值',
+        sessionKeyFormat: 'sessionKey 通常以 sk-ant-sid01- 开头',
        startAutoAuth: '开始自动授权',
        authorizing: '授权中...',
        followSteps: '按照以下步骤授权您的 Claude 账号：',
@@ -1296,9 +1297,9 @@ export default {
        step2OpenUrl: '在浏览器中打开 URL 并完成授权',
        openUrlDesc: '在新标签页中打开授权 URL，登录您的 Claude 账号并授权。',
        proxyWarning:
-          '<strong>注意：</strong>如果您配置了代理，请确保浏览器使用相同的代理访问授权页面。',
+          '注意：如果您配置了代理，请确保浏览器使用相同的代理访问授权页面。',
        step3EnterCode: '输入授权码',
-        authCodeDesc: '授权完成后，页面会显示一个 <strong>授权码</strong>。复制并粘贴到下方：',
+        authCodeDesc: '授权完成后，页面会显示一个授权码。复制并粘贴到下方：',
        authCode: '授权码',
        authCodePlaceholder: '粘贴 Claude 页面的授权码...',
        authCodeHint: '粘贴从 Claude 页面复制的授权码',
@@ -1318,10 +1319,10 @@ export default {
          step2OpenUrl: '在浏览器中打开链接并完成授权',
          openUrlDesc: '请在新标签页中打开授权链接，登录您的 OpenAI 账户并授权。',
          importantNotice:
-            '<strong>重要提示：</strong>授权后页面可能会加载较长时间，请耐心等待。当浏览器地址栏变为 <code>http://localhost...</code> 开头时，表示授权已完成。',
+            '重要提示：授权后页面可能会加载较长时间，请耐心等待。当浏览器地址栏变为 http://localhost... 开头时，表示授权已完成。',
          step3EnterCode: '输入授权链接或 Code',
          authCodeDesc:
-            '授权完成后，当页面地址变为 <code>http://localhost:xxx/auth/callback?code=...</code> 时：',
+            '授权完成后，当页面地址变为 http://localhost:xxx/auth/callback?code=... 时：',
          authCode: '授权链接或 Code',
          authCodePlaceholder:
            '方式1：复制完整的链接\n(http://localhost:xxx/auth/callback?code=...)\n方式2：仅复制 code 参数的值',
@@ -1340,7 +1341,7 @@ export default {
 	          step2OpenUrl: '在浏览器中打开链接并完成授权',
 	          openUrlDesc: '请在新标签页中打开授权链接，登录您的 Google 账户并授权。',
 	          step3EnterCode: '输入回调链接或 Code',
-	          authCodeDesc: '授权完成后，复制浏览器跳转后的回调链接（推荐）或仅复制 <code>code</code>，粘贴到下方即可。',
+	          authCodeDesc: '授权完成后，复制浏览器跳转后的回调链接（推荐）或仅复制 code，粘贴到下方即可。',
 	          authCode: '回调链接或 Code',
 	          authCodePlaceholder: '方式1（推荐）：粘贴回调链接\n方式2：仅粘贴 code 参数的值',
 	          authCodeHint: '系统会自动从链接中解析 code/state。',
@@ -1376,10 +1377,10 @@ export default {
          step2OpenUrl: '在浏览器中打开链接并完成授权',
          openUrlDesc: '请在新标签页中打开授权链接，登录您的 Google 账户并授权。',
          importantNotice:
-            '<strong>重要提示：</strong>授权后页面可能会加载较长时间，请耐心等待。当浏览器地址栏变为 <code>http://localhost...</code> 开头时，表示授权已完成。',
+            '重要提示：授权后页面可能会加载较长时间，请耐心等待。当浏览器地址栏变为 http://localhost... 开头时，表示授权已完成。',
          step3EnterCode: '输入授权链接或 Code',
          authCodeDesc:
-            '授权完成后，当页面地址变为 <code>http://localhost:xxx/auth/callback?code=...</code> 时：',
+            '授权完成后，当页面地址变为 http://localhost:xxx/auth/callback?code=... 时：',
          authCode: '授权链接或 Code',
          authCodePlaceholder:
            '方式1：复制完整的链接\n(http://localhost:xxx/auth/callback?code=...)\n方式2：仅复制 code 参数的值',
@@ -1847,8 +1848,8 @@ export default {
        secretKey: '私密密钥',
        siteKeyHint: '从 Cloudflare Dashboard 获取',
        cloudflareDashboard: 'Cloudflare Dashboard',
-        secretKeyHint: '服务端验证密钥（请保密）'
-      },
+        secretKeyHint: '服务端验证密钥（请保密）',
+        secretKeyConfiguredHint: '密钥已配置，留空以保留当前值。'      },
      defaults: {
        title: '用户默认设置',
        description: '新用户的默认值',
@@ -1897,6 +1898,8 @@ export default {
        password: 'SMTP 密码',
        passwordPlaceholder: '********',
        passwordHint: '留空以保留现有密码',
+        passwordConfiguredPlaceholder: '********',
+        passwordConfiguredHint: '密码已配置，留空以保留当前值。',
        fromEmail: '发件人邮箱',
        fromEmailPlaceholder: "noreply{'@'}example.com",
        fromName: '发件人名称',
--- a/frontend/src/utils/url.ts
+++ b/frontend/src/utils/url.ts
@@ -0,0 +1,37 @@
+/**
+ * 验证并规范化 URL
+ * 默认只接受绝对 URL（以 http:// 或 https:// 开头），可按需允许相对路径
+ * @param value 用户输入的 URL
+ * @returns 规范化后的 URL，如果无效则返回空字符串
+ */
+type SanitizeOptions = {
+  allowRelative?: boolean
+}
+
+export function sanitizeUrl(value: string, options: SanitizeOptions = {}): string {
+  const trimmed = value.trim()
+  if (!trimmed) {
+    return ''
+  }
+
+  if (options.allowRelative && trimmed.startsWith('/') && !trimmed.startsWith('//')) {
+    return trimmed
+  }
+
+  // 只接受绝对 URL，不使用 base URL 来避免相对路径被解析为当前域名
+  // 检查是否以 http:// 或 https:// 开头
+  if (!trimmed.match(/^https?:\/\//i)) {
+    return ''
+  }
+
+  try {
+    const parsed = new URL(trimmed)
+    const protocol = parsed.protocol.toLowerCase()
+    if (protocol !== 'http:' && protocol !== 'https:') {
+      return ''
+    }
+    return parsed.toString()
+  } catch {
+    return ''
+  }
+}
--- a/frontend/src/views/HomeView.vue
+++ b/frontend/src/views/HomeView.vue
@@ -493,6 +493,7 @@ import { useI18n } from 'vue-i18n'
 import { getPublicSettings } from '@/api/auth'
 import { useAuthStore } from '@/stores'
 import LocaleSwitcher from '@/components/common/LocaleSwitcher.vue'
+import { sanitizeUrl } from '@/utils/url'

 const { t } = useI18n()

@@ -549,9 +550,9 @@ onMounted(async () => {
  try {
    const settings = await getPublicSettings()
    siteName.value = settings.site_name || 'Sub2API'
-    siteLogo.value = settings.site_logo || ''
+    siteLogo.value = sanitizeUrl(settings.site_logo || '', { allowRelative: true })
    siteSubtitle.value = settings.site_subtitle || 'AI API Gateway Platform'
-    docUrl.value = settings.doc_url || ''
+    docUrl.value = sanitizeUrl(settings.doc_url || '', { allowRelative: true })
  } catch (error) {
    console.error('Failed to load public settings:', error)
  }
--- a/frontend/src/views/admin/SettingsView.vue
+++ b/frontend/src/views/admin/SettingsView.vue
@@ -255,7 +255,11 @@
                    placeholder="0x4AAAAAAA..."
                  />
                  <p class="mt-1.5 text-xs text-gray-500 dark:text-gray-400">
-                    {{ t('admin.settings.turnstile.secretKeyHint') }}
+                    {{
+                      form.turnstile_secret_key_configured
+                        ? t('admin.settings.turnstile.secretKeyConfiguredHint')
+                        : t('admin.settings.turnstile.secretKeyHint')
+                    }}
                  </p>
                </div>
              </div>
@@ -577,10 +581,18 @@
                  v-model="form.smtp_password"
                  type="password"
                  class="input"
-                  :placeholder="t('admin.settings.smtp.passwordPlaceholder')"
+                  :placeholder="
+                    form.smtp_password_configured
+                      ? t('admin.settings.smtp.passwordConfiguredPlaceholder')
+                      : t('admin.settings.smtp.passwordPlaceholder')
+                  "
                />
                <p class="mt-1.5 text-xs text-gray-500 dark:text-gray-400">
-                  {{ t('admin.settings.smtp.passwordHint') }}
+                  {{
+                    form.smtp_password_configured
+                      ? t('admin.settings.smtp.passwordConfiguredHint')
+                      : t('admin.settings.smtp.passwordHint')
+                  }}
                </p>
              </div>
              <div>
@@ -713,7 +725,7 @@
 import { ref, reactive, onMounted } from 'vue'
 import { useI18n } from 'vue-i18n'
 import { adminAPI } from '@/api'
-import type { SystemSettings } from '@/api/admin/settings'
+import type { SystemSettings, UpdateSettingsRequest } from '@/api/admin/settings'
 import AppLayout from '@/components/layout/AppLayout.vue'
 import Toggle from '@/components/common/Toggle.vue'
 import { useAppStore } from '@/stores'
@@ -735,7 +747,12 @@ const adminApiKeyMasked = ref('')
 const adminApiKeyOperating = ref(false)
 const newAdminApiKey = ref('')

-const form = reactive<SystemSettings>({
+type SettingsForm = SystemSettings & {
+  smtp_password: string
+  turnstile_secret_key: string
+}
+
+const form = reactive<SettingsForm>({
  registration_enabled: true,
  email_verify_enabled: false,
  default_balance: 0,
@@ -750,13 +767,15 @@ const form = reactive<SystemSettings>({
  smtp_port: 587,
  smtp_username: '',
  smtp_password: '',
+  smtp_password_configured: false,
  smtp_from_email: '',
  smtp_from_name: '',
  smtp_use_tls: true,
  // Cloudflare Turnstile
  turnstile_enabled: false,
  turnstile_site_key: '',
-  turnstile_secret_key: ''
+  turnstile_secret_key: '',
+  turnstile_secret_key_configured: false
 })

 function handleLogoUpload(event: Event) {
@@ -802,6 +821,8 @@ async function loadSettings() {
  try {
    const settings = await adminAPI.settings.getSettings()
    Object.assign(form, settings)
+    form.smtp_password = ''
+    form.turnstile_secret_key = ''
  } catch (error: any) {
    appStore.showError(
      t('admin.settings.failedToLoad') + ': ' + (error.message || t('common.unknownError'))
@@ -814,7 +835,32 @@ async function loadSettings() {
 async function saveSettings() {
  saving.value = true
  try {
-    await adminAPI.settings.updateSettings(form)
+    const payload: UpdateSettingsRequest = {
+      registration_enabled: form.registration_enabled,
+      email_verify_enabled: form.email_verify_enabled,
+      default_balance: form.default_balance,
+      default_concurrency: form.default_concurrency,
+      site_name: form.site_name,
+      site_logo: form.site_logo,
+      site_subtitle: form.site_subtitle,
+      api_base_url: form.api_base_url,
+      contact_info: form.contact_info,
+      doc_url: form.doc_url,
+      smtp_host: form.smtp_host,
+      smtp_port: form.smtp_port,
+      smtp_username: form.smtp_username,
+      smtp_password: form.smtp_password || undefined,
+      smtp_from_email: form.smtp_from_email,
+      smtp_from_name: form.smtp_from_name,
+      smtp_use_tls: form.smtp_use_tls,
+      turnstile_enabled: form.turnstile_enabled,
+      turnstile_site_key: form.turnstile_site_key,
+      turnstile_secret_key: form.turnstile_secret_key || undefined
+    }
+    const updated = await adminAPI.settings.updateSettings(payload)
+    Object.assign(form, updated)
+    form.smtp_password = ''
+    form.turnstile_secret_key = ''
    // Refresh cached public settings so sidebar/header update immediately
    await appStore.fetchPublicSettings(true)
    appStore.showSuccess(t('admin.settings.settingsSaved'))
--- a/frontend/src/views/auth/LoginView.vue
+++ b/frontend/src/views/auth/LoginView.vue
@@ -277,6 +277,14 @@ const errors = reactive({
 // ==================== Lifecycle ====================

 onMounted(async () => {
+  const expiredFlag = sessionStorage.getItem('auth_expired')
+  if (expiredFlag) {
+    sessionStorage.removeItem('auth_expired')
+    const message = t('auth.reloginRequired')
+    errorMessage.value = message
+    appStore.showWarning(message)
+  }
+
  try {
    const settings = await getPublicSettings()
    turnstileEnabled.value = settings.turnstile_enabled