diff --git a/internal/middleware/cors.go b/internal/middleware/cors.go
new file mode 100644
index 0000000..109a431
--- /dev/null
+++ b/internal/middleware/cors.go
@@ -0,0 +1,49 @@
+package middleware
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+
+	"gotest/internal/config"
+)
+
+// CORS 跨域中间件，根据配置放行指定来源
+func CORS(cfg *config.CORSConfig) gin.HandlerFunc {
+	allowed := make(map[string]bool)
+	wildcard := false
+	for _, origin := range cfg.AllowedOrigins {
+		if origin == "*" {
+			// 配置中包含 * 表示通配，允许任意来源
+			wildcard = true
+			continue
+		}
+		allowed[origin] = true
+	}
+
+	return func(c *gin.Context) {
+		origin := c.GetHeader("Origin")
+		switch {
+		case wildcard:
+			// 通配模式直接放行所有来源
+			c.Header("Access-Control-Allow-Origin", "*")
+		case origin != "" && allowed[origin]:
+			// 命中白名单时回写具体来源，并标注 Vary 以便缓存正确
+			c.Header("Access-Control-Allow-Origin", origin)
+			c.Header("Vary", "Origin")
+		}
+
+		c.Header("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS, PATCH")
+		c.Header("Access-Control-Allow-Headers", "Origin, Content-Type, Authorization, X-Requested-With")
+		c.Header("Access-Control-Allow-Credentials", "true")
+		c.Header("Access-Control-Max-Age", "86400")
+
+		// 处理 OPTIONS 预检请求，直接返回 204
+		if c.Request.Method == http.MethodOptions {
+			c.AbortWithStatus(http.StatusNoContent)
+			return
+		}
+
+		c.Next()
+	}
+}