Overview
Broken Object Level Authorization (BOLA) occurs when an API exposes an object-specific endpoint without validating that the requester is allowed to access the exact instance. CVE-2026-24069 exposes this pattern in Kiuwan SAST: improperly authorizing SSO logins for locally disabled mapped user accounts allowed disabled users to continue accessing the application. This kind of flaw can appear in services written in Go using Gin when object IDs in route parameters are trusted by the server without verifying ownership or privileges.
In a Go (Gin) API, a common vulnerable pattern is to fetch a resource by its ID from the URL and return it to the caller without checking that the authenticated user owns the resource or has permission to view it. An attacker who can enumerate IDs could access or modify other users' data simply by changing the path parameter. The Kiuwan CVE demonstrates how identity mapping and session authorization failures enable continued access even after accounts should have been disabled, which is a BOLA symptom.
Fixing this in Go (Gin) requires enforcing authorization on every object access. After authenticating the user, validate ownership or admin privileges before returning the object. Prefer centralizing access control (middleware or service layer), avoid trusting client-provided IDs, and add targeted tests that cover cross-user access attempts. The included code sample shows a vulnerable handler and a fixed handler side-by-side to illustrate the remediation.
Code Fix Example
Go (Gin) API Security Remediation
package main
import (
"net/http"
"strings"
"github.com/gin-gonic/gin"
)
type User struct { ID string; IsAdmin bool }
type Resource struct { ID string; OwnerID string; Data string }
var resources map[string]Resource
func main() {
r := gin.Default()
seedResources()
// public endpoints: vulnerable and fixed for demonstration
r.GET("/vulnerable/resource/:id", vulnerableHandler)
r.GET("/fixed/resource/:id", fixedHandler)
// simple auth middleware to populate user context
r.Use(authMiddleware)
r.Run(":8080")
}
func seedResources() {
resources = map[string]Resource{
"1": {ID:"1", OwnerID:"alice", Data:"secret1"},
"2": {ID:"2", OwnerID:"bob", Data:"secret2"},
}
}
func authMiddleware(c *gin.Context) {
auth := c.GetHeader("Authorization")
if strings.HasPrefix(auth, "Bearer ") {
userID := strings.TrimPrefix(auth, "Bearer ")
c.Set("user", &User{ID: userID, IsAdmin: false})
} else {
c.Set("user", &User{ID: "anonymous", IsAdmin: false})
}
c.Next()
}
func vulnerableHandler(c *gin.Context) {
id := c.Param("id")
res, ok := resources[id]
if !ok {
c.JSON(http.StatusNotFound, gin.H{\"error\": \"not found\"})
return
}
// VULNERABLE: no authorization check
c.JSON(http.StatusOK, res)
}
func fixedHandler(c *gin.Context) {
id := c.Param("id")
res, ok := resources[id]
if !ok {
c.JSON(http.StatusNotFound, gin.H{\"error\": \"not found\"})
return
}
user, _ := c.Get("user")
u := user.(*User)
if res.OwnerID != u.ID && !u.IsAdmin {
c.JSON(http.StatusForbidden, gin.H{\"error\": \"forbidden\"})
return
}
c.JSON(http.StatusOK, res)
}