---
id: GHSA-46wh-3698-f2cx
aliases:
  - GO-2026-4897
title: >-
  Traefik: Deny Rule Bypass via Unauthenticated Malicious gRPC Requests in
  gRPC-Go Dependency (CVE-2026-33186)
summary: >-
  Traefik: Deny Rule Bypass via Unauthenticated Malicious gRPC Requests in
  gRPC-Go Dependency (CVE-2026-33186)
severity: high
vendor: traefik
product: github.com/traefik/traefik/v2
ecosystem: go
affected:
  - github.com/traefik/traefik/v2 < 2.11.42
  - 'github.com/traefik/traefik/v3 >= 3.0.0-beta3, < 3.6.12'
  - 'github.com/traefik/traefik/v3 >= 3.7.0-ea.1, < 3.7.0-ea.3'
patched:
  - github.com/traefik/traefik/v2 2.11.42
  - github.com/traefik/traefik/v3 3.6.12
  - github.com/traefik/traefik/v3 3.7.0-ea.3
published: '2026-03-29'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T03:50:36.980577799Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-46wh-3698-f2cx'
references:
  - url: 'https://github.com/traefik/traefik/security/advisories/GHSA-46wh-3698-f2cx'
  - url: 'https://github.com/advisories/GHSA-p77j-4mvh-x3m3'
  - url: 'https://github.com/traefik/traefik'
  - url: >-
      https://github.com/traefik/traefik/blob/67c64ed9b25fbb90f1086977a62827133a7aa01b/go.mod#L108
  - url: 'https://github.com/traefik/traefik/releases/tag/v2.11.42'
  - url: 'https://github.com/traefik/traefik/releases/tag/v3.6.12'
  - url: 'https://github.com/traefik/traefik/releases/tag/v3.7.0-ea.3'
tags:
  - osv
  - go
ingestedAt: '2026-09-12T03:13:01.751Z'
---

## Overview

## Summary

There is a potential vulnerability in Traefik due to its dependency on an affected version of gRPC-Go (CVE-2026-33186).

A remote, unauthenticated attacker can send gRPC requests with a malformed HTTP/2 `:path` pseudo-header omitting the mandatory leading slash (e.g., `Service/Method` instead of `/Service/Method`). While the server routes such requests correctly, path-based authorization interceptors evaluate the raw non-canonical path and fail to match "deny" rules, allowing the request to bypass the policy entirely if a fallback "allow" rule is present.

## Patches

- https://github.com/traefik/traefik/releases/tag/v2.11.42
- https://github.com/traefik/traefik/releases/tag/v3.6.12
- https://github.com/traefik/traefik/releases/tag/v3.7.0-ea.3

## For more information

If there are any questions or comments about this advisory, please [open an issue](https://github.com/traefik/traefik/issues).

<details>
<summary>Original Description</summary>

### Summary
This CVE hits traefik until Version 3.6.11 and 2.11.41.
gRPC-Go has an authorization bypass via missing leading slash in :path
### Details
As described in https://github.com/advisories/GHSA-p77j-4mvh-x3m3
### PoC
Update library version in 
https://github.com/traefik/traefik/blob/67c64ed9b25fbb90f1086977a62827133a7aa01b/go.mod#L108
### Impact
Is described in https://github.com/advisories/GHSA-p77j-4mvh-x3m3

</details>


----------

## Affected packages

- `github.com/traefik/traefik/v2 < 2.11.42`
- `github.com/traefik/traefik/v3 >= 3.0.0-beta3, < 3.6.12`
- `github.com/traefik/traefik/v3 >= 3.7.0-ea.1, < 3.7.0-ea.3`

## Remediation

Upgrade to a patched release:

- `github.com/traefik/traefik/v2 2.11.42`
- `github.com/traefik/traefik/v3 3.6.12`
- `github.com/traefik/traefik/v3 3.7.0-ea.3`