---
id: CVE-2026-88008
title: Traefik is an open source HTTP reverse proxy and load balancer
summary: >-
  Traefik is an open source HTTP reverse proxy and load balancer. From 2.11.26
  until 2.11.57 and 3.7.13, Traefik forwards a client-supplied Connection header
  requesting Upgrade, the Upgrade: h2c token, and HTTP2-Settings to a shared
  backen…
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-444
  - CWE-863
vendor: traefik
product: traefik
affected:
  - 'traefik >= 2.11.26, < 2.11.57'
  - 'traefik >= 3.4.2, < 3.7.13'
patched:
  - traefik 3.7.13
published: '2026-09-10'
updated: '2026-09-14'
sourceUpdated: '2026-09-14T19:59:04.550'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-88008'
references:
  - url: >-
      https://github.com/traefik/traefik/commit/a277e94664ffc1ce9543df552d3bbf48d4d3b8b3
    label: security-advisories@github.com
  - url: 'https://github.com/traefik/traefik/pull/13797'
    label: security-advisories@github.com
  - url: 'https://github.com/traefik/traefik/releases/tag/v2.11.57'
    label: security-advisories@github.com
  - url: 'https://github.com/traefik/traefik/releases/tag/v3.7.13'
    label: security-advisories@github.com
  - url: 'https://github.com/traefik/traefik/security/advisories/GHSA-w4v4-9rw7-5326'
    label: security-advisories@github.com
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-88008'
  - url: 'https://github.com/traefik/traefik'
tags:
  - nvd
  - cve.org
  - osv
  - go
  - score-dispute
epss: 0.00487
epssPercentile: 0.39272
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-10T16:54:44.054899Z'
scores:
  nvd: 9.1
  cna: 7
ingestedAt: '2026-09-11T14:42:19.869Z'
aliases:
  - GHSA-w4v4-9rw7-5326
  - GO-2026-6468
ecosystem: go
---

## Overview

Traefik is an open source HTTP reverse proxy and load balancer. From 2.11.26 until 2.11.57 and 3.7.13, Traefik forwards a client-supplied Connection header requesting Upgrade, the Upgrade: h2c token, and HTTP2-Settings to a shared backend. If the backend accepts h2c and returns 101 Switching Protocols, Traefik enters a raw tunnel and no longer applies routers, BasicAuth, ForwardAuth, IPAllowList, RateLimit, access logging, metrics, or tracing to later HTTP/2 requests, allowing an unauthenticated request through an unprotected route to reach protected paths on the same backend. This issue is fixed in 2.11.57 and 3.7.13.

## Affected

- `traefik >= 2.11.26, < 2.11.57`
- `traefik >= 3.4.2, < 3.7.13`

## Remediation

Upgrade past the affected range:

- `traefik 3.7.13`

## Package advisory (CVE-2026-88008)

Affected packages:

- `github.com/traefik/traefik/v3 >= 3.4.2, < 3.7.13`
- `github.com/traefik/traefik/v2 >= 2.11.26, < 2.11.57`

Patched in:

- `github.com/traefik/traefik/v3 3.7.13`
- `github.com/traefik/traefik/v2 2.11.57`

Source: https://osv.dev/vulnerability/GHSA-w4v4-9rw7-5326