Vulnerability CVE-2026-35051: Information

Description

Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is an authentication bypass vulnerability in Traefik's ForwardAuth middleware when trustForwardHeader=false is configured and Traefik is deployed behind a trusted upstream proxy. This issue has been patched in versions 2.11.43, 3.6.14, and 3.7.0-rc.2.

Severity: HIGH (7.8)

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Severity: CRITICAL (10.0)

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

URL: https://nvd.nist.gov/vuln/detail/CVE-2026-35051

Published: April 30, 2026

Modified: May 1, 2026

Error type identifier: CWE-345

Fixed packages

Package name	Branch	Fixed in version	Version from repository	Errata ID	Task #	State
traefik	sisyphus	3.6.15-alt1	3.6.15-alt1	ALT-PU-2026-7142-3	417190	Fixed
traefik	p11	3.6.15-alt1	3.6.15-alt1	ALT-PU-2026-7164-3	417230	Fixed
traefik	c10f2	3.6.15-alt1	3.6.15-alt1	ALT-PU-2026-7154-3	417229	Fixed

References to Advisories, Solutions, and Tools

Hyperlink	Resource
https://github.com/traefik/traefik/releases/tag/v2.11.43	Product Release Notes
https://github.com/traefik/traefik/releases/tag/v3.6.14	Product Release Notes
https://github.com/traefik/traefik/releases/tag/v3.7.0-rc.2	Product Release Notes
https://github.com/traefik/traefik/security/advisories/GHSA-6384-m2mw-rf54	Exploit Patch Vendor Advisory
GHSA-6384-m2mw-rf54

Affected configurations:
1. cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*
  End excluding
  2.11.43
  cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*
  Start including
  3.0.0
  End excluding
  3.6.14
  cpe:2.3:a:traefik:traefik:3.7.0:ea1:*:*:*:*:*:*
  cpe:2.3:a:traefik:traefik:3.7.0:ea2:*:*:*:*:*:*
  cpe:2.3:a:traefik:traefik:3.7.0:ea3:*:*:*:*:*:*
  cpe:2.3:a:traefik:traefik:3.7.0:rc1:*:*:*:*:*:*

Version: v26.2.2