---
id: CVE-2026-88004
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 3.2.0
  until 3.7.13, Traefik entrypoint defenses aliasHeadersStrategy,
  underscoreHeadersStrategy, and forwardedHeaders inspect req.Header but not
  req.Trailer, allowing a…
severity: high
cvss: 7.4
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-436
  - CWE-807
vendor: traefik
product: traefik
affected:
  - 'traefik >= 3.2.0, < 3.7.13'
patched:
  - traefik 3.7.13
published: '2026-09-10'
updated: '2026-09-14'
sourceUpdated: '2026-09-14T19:58:45.057'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-88004'
references:
  - url: >-
      https://github.com/traefik/traefik/commit/55bbda4f65e0f9c533c870983a767a7081126db7
    label: security-advisories@github.com
  - url: 'https://github.com/traefik/traefik/pull/13822'
    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-v67p-phpq-fc8x'
    label: security-advisories@github.com
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-88004'
  - url: 'https://github.com/traefik/traefik'
tags:
  - nvd
  - cve.org
  - osv
  - go
epss: 0.00273
epssPercentile: 0.19877
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-10T15:10:37.863514Z'
scores:
  nvd: 7.4
  cna: 7
ingestedAt: '2026-09-12T17:19:30.639Z'
aliases:
  - GHSA-v67p-phpq-fc8x
  - GO-2026-6467
ecosystem: go
---

## Overview

Traefik is an open source HTTP reverse proxy and load balancer. From 3.2.0 until 3.7.13, Traefik entrypoint defenses aliasHeadersStrategy, underscoreHeadersStrategy, and forwardedHeaders inspect req.Header but not req.Trailer, allowing an unauthenticated client to submit an aliasing or trusted header name in an HTTP/1.1 chunked trailer or an HTTP/2 trailer. When the retry or buffering middleware reads the body before the reverse proxy clones the request, the attacker-controlled trailer value reaches a backend that merges trailers into the header namespace, bypassing the documented delete or reject behavior and potentially spoofing identity or forwarded routing data. This issue is fixed in 3.7.13.

## Affected

- `traefik >= 3.2.0, < 3.7.13`

## Remediation

Upgrade past the affected range:

- `traefik 3.7.13`

## Package advisory (CVE-2026-88004)

Affected packages:

- `github.com/traefik/traefik/v3 >= 3.2.0, < 3.7.13`

Patched in:

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

Source: https://osv.dev/vulnerability/GHSA-v67p-phpq-fc8x