GHSA-XFX2-PRG5-JQ3G: Gin-Gonic Middleware Bypass: Authorization Failure in INSATutorat

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Gin-Gonic Middleware Bypass: Authorization Failure in INSATutorat

Vulnerability ID: GHSA-XFX2-PRG5-JQ3G
CVSS Score: 8.8
Published: 2026-03-01

A critical authorization bypass vulnerability exists in the INSATutorat application due to improper middleware implementation within the Gin-Gonic web framework. The AdminHandler middleware, designed to protect administrative routes, fails to terminate the request lifecycle upon detecting unauthorized access. Consequently, authenticated non-administrative users can bypass security controls and execute privileged actions on endpoints under /api/admin/*, resulting in potential data loss and unauthorized system management.

TL;DR

The INSATutorat application contains a critical flaw in its administrative middleware. While the code correctly identifies unauthorized users, it fails to halt the request processing chain (missing c.Abort()). This allows any authenticated user to successfully invoke administrative API endpoints regardless of their privileges.

⚠️ Exploit Status: POC

Technical Details

CWE ID: CWE-285
CVSS v3.1: 8.8
Attack Vector: Network
Privileges Required: Low
Impact: High (Confidentiality & Integrity)
Platform: Go (Gin-Gonic)

Affected Systems

INSATutorat (Go Application)
INSATutorat: < 15ae47425aed337181f7a6c54a9d199c93b041eb (Fixed in: 15ae47425aed337181f7a6c54a9d199c93b041eb)

Code Analysis

Commit: 15ae474

Fix admin middleware authorization bypass by adding c.Abort()

func AdminHandler() gin.HandlerFunc {
        userInterface, exists := c.Get("user")
        if !exists {
            _ = c.Error(apierrors.Unauthorized)
+           c.Abort()
            return
        }

        user := userInterface.(*models.User)
        if !user.IsAdmin {
            _ = c.Error(apierrors.Forbidden)
+           c.Abort()
            return
        }
    }

Mitigation Strategies

Immediate patching of the middleware logic.
Audit of all Gin middleware for missing Abort() calls.
Implementation of integration tests that specifically assert HTTP status codes for unauthorized requests.

Remediation Steps:

Locate middlewares/admin.go in the source code.
Insert c.Abort() immediately before return in all error handling branches.
Rebuild and redeploy the application.
Verify the fix by attempting to access /api/admin/ endpoints with a non-admin account.

References

Read the full report for GHSA-XFX2-PRG5-JQ3G on our website for more details including interactive diagrams and full exploit analysis.

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