---
id: CVE-2026-71324
title: Traefik is an open source HTTP reverse proxy and load balancer
summary: >-
  Traefik is an open source HTTP reverse proxy and load balancer. Prior to
  2.11.53, 3.6.24, and 3.7.9, Traefik's default HTTP reverse proxy forwards a
  plain HTTP/2 or HTTP/3 CONNECT request and its body to an HTTP/1.1 upstream
  through a sh…
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
vendor: traefik
product: traefik
affected:
  - traefik < 2.11.53
  - 'traefik >= 3.0.0, < 3.6.24'
  - 'traefik >= 3.7.0, < 3.7.9'
patched:
  - traefik 3.7.9
published: '2026-08-06'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T20:46:12.443'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-71324'
references:
  - url: >-
      https://github.com/traefik/traefik/commit/04d36f28e4eae7535e96a6351dd9f7bfb48a30e7
    label: security-advisories@github.com
  - url: >-
      https://github.com/traefik/traefik/commit/0807b6d5dd1da8b2f7f4076ea2392b5437bf2ab0
    label: security-advisories@github.com
  - url: >-
      https://github.com/traefik/traefik/commit/94a7508817d180f0ab2f1eae93df48d4ab19ecce
    label: security-advisories@github.com
  - url: 'https://github.com/traefik/traefik/pull/13542'
    label: security-advisories@github.com
  - url: 'https://github.com/traefik/traefik/pull/13543'
    label: security-advisories@github.com
  - url: 'https://github.com/traefik/traefik/pull/13556'
    label: security-advisories@github.com
  - url: 'https://github.com/traefik/traefik/releases/tag/v2.11.53'
    label: security-advisories@github.com
  - url: 'https://github.com/traefik/traefik/releases/tag/v3.6.24'
    label: security-advisories@github.com
  - url: 'https://github.com/traefik/traefik/releases/tag/v3.7.9'
    label: security-advisories@github.com
  - url: 'https://github.com/traefik/traefik/security/advisories/GHSA-3ccp-42pg-hgv6'
    label: security-advisories@github.com
  - url: 'https://github.com/advisories/GHSA-3ccp-42pg-hgv6'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-71324.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-71324'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2512342'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-71324'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-71324'
tags:
  - nvd
  - ghsa
  - go
  - csaf
  - vex
  - red-hat
epss: 0.00693
epssPercentile: 0.50868
aliases:
  - GHSA-3ccp-42pg-hgv6
ecosystem: go
ingestedAt: '2026-08-06T16:00:00.460Z'
scores:
  nvd: 9.1
  vendor: 8.6
---

## Overview

Traefik is an open source HTTP reverse proxy and load balancer. Prior to 2.11.53, 3.6.24, and 3.7.9, Traefik's default HTTP reverse proxy forwards a plain HTTP/2 or HTTP/3 CONNECT request and its body to an HTTP/1.1 upstream through a shared net/http.Transport. When the upstream answers the CONNECT with a keep-alive non-2xx response and does not drain the body, Traefik returns the desynchronized backend socket to its shared pool and reuses it for other clients. An unauthenticated attacker can use this behavior to make a different client read the attacker's smuggled response, which can include authenticated or private content from another request. The ForwardAuth middleware with forwardBody true and preserveRequestMethod true can re-issue a CONNECT with the buffered body attached, exposing the auth-client pool to the same desynchronization. This issue is fixed in 2.11.53, 3.6.24, and 3.7.9.

## Affected

- `traefik < 2.11.53`
- `traefik >= 3.0.0, < 3.6.24`
- `traefik >= 3.7.0, < 3.7.9`

## Remediation

Upgrade past the affected range:

- `traefik 3.7.9`

## Package advisory (CVE-2026-71324)

Affected packages:

- `github.com/traefik/traefik/v2 <= 2.11.52`
- `github.com/traefik/traefik/v3 <= 3.6.23`
- `github.com/traefik/traefik/v3 >= 3.7.0, <= 3.7.8`
- `github.com/traefik/traefik <= 1.7.34`

Patched in:

- `github.com/traefik/traefik/v2 2.11.53`
- `github.com/traefik/traefik/v3 3.6.24`
- `github.com/traefik/traefik/v3 3.7.9`

Source: https://github.com/advisories/GHSA-3ccp-42pg-hgv6

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat OpenShift Dev Spaces · no fix planned: Red Hat OpenShift Dev Spaces · updated 2026-09-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-71324.json)