What’s Vulnerable › Vulnerabilities

CVE-2026-54764: ForwardAuth middleware leaks X-Forwarded-Port spoofing via untrusted X-Forwarded-Proto when trustForwardHeader=false

• Severity: medium (CVSS 5.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-06 · updated 2026-07-08
• Weakness: CWE-345

Description

Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Traefik's ForwardAuth middleware, even when configured with trustForwardHeader: false, derives the X-Forwarded-Port header sent to the authentication service from the original incoming request instead of the sanitized forwarded request. As a result, an unauthenticated remote attacker can inject an X-Forwarded-Proto: https header over a plain HTTP connection and cause Traefik to forward X-Forwarded-Port: 443 to the authentication service, bypassing port-based authorization checks. This issue is fixed in versions v2.11.51, v3.6.22, and v3.7.6.

Affected products

• Traefik: before 2.11.51; from 3.0.0 before 3.6.22; from 3.7.0 before 3.7.6 — fixed in 2.11.51, 3.6.22, 3.7.6

How to fix

Upgrade to a fixed version: Traefik 2.11.51, 3.6.22, 3.7.6. Check the vendor advisory for mitigations.

References

• https://github.com/traefik/traefik/commit/7ae92d8c2c10ac04ef5a03df0ed5019ce0f44b2d
• https://github.com/traefik/traefik/pull/13344
• https://github.com/traefik/traefik/security/advisories/GHSA-3q9r-p662-5j8m

Get alerted when CVE-2026-54764 or the next vulnerability affects your stack