Overview
CVE-2025-70810 describes a Cross Site Request Forgery vulnerability in phpBB phbb3 v.3.3.15 that allows a local attacker to exploit the login function and authentication mechanism to run arbitrary code. While this CVE is in a PHP project, it exemplifies how broken authentication and CSRF flaws in login flows can enable unauthorized state changes or even code execution when an attacker can coerce a user into making a request within an authenticated context. In Go and the Gin framework, similar CSRF- or authentication-flow weaknesses can occur if login endpoints are exposed via GET, lack token validation, or rely solely on cookies without anti-forgery protections. This guide maps those lessons to Go (Gin) implementations and provides concrete remediation code.
Code Fix Example
Go (Gin) API Security Remediation
package main
import (
"net/http"
"github.com/gin-gonic/gin"
csrf "github.com/utrack/gin-csrf"
)
func main() {
r := gin.New()
r.Use(gin.Logger())
r.Use(gin.Recovery())
// Vulnerable: login via GET with query params and no CSRF protection
r.GET("/login_vuln", func(c *gin.Context) {
user := c.Query("username")
pass := c.Query("password")
if user == "admin" && pass == "secret" {
c.SetCookie("session_id", "sess-"+user, 3600, "/", "localhost", true, true)
c.String(http.StatusOK, "Logged in (vulnerable)")
return
}
c.String(http.StatusUnauthorized, "Denied")
})
// CSRF-protected path: CSRF middleware applied to this group
protected := r.Group("/")
protected.Use(csrf.Middleware(csrf.Options{
Secret: "secret123",
ErrorFunc: func(c *gin.Context) {
c.String(http.StatusForbidden, "CSRF token invalid")
c.Abort()
},
}))
protected.POST("/login_fix", func(c *gin.Context) {
username := c.PostForm("username")
password := c.PostForm("password")
if username == "admin" && password == "secret" {
c.SetCookie("session_id", "sess-"+username, 3600, "/", "localhost", true, true)
c.String(http.StatusOK, "Logged in (fixed)")
} else {
c.String(http.StatusUnauthorized, "Denied")
}
})
// Endpoint to fetch CSRF token for client usage
r.GET("/csrf-token", func(c *gin.Context) {
c.JSON(http.StatusOK, gin.H{"csrf_token": csrf.GetToken(c)})
})
r.Run(":8080")
}