CVE-2026-54764
MediumCVSS 5.8Exploitation Probability (EPSS)
Low risk21th percentile - higher than 21% of all known CVEs
Summary
In Traefik prior to versions v2.11.51, v3.6.22, and v3.7.6, the ForwardAuth middleware, even when configured with trustForwardHeader: false, derives the X-Forwarded-Port header from the original incoming request instead of the sanitized forwarded request. 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.
Risk Assessment
The organization is at risk of bypassing port-based authorization, potentially allowing an unauthenticated attacker to gain unauthorized access to protected resources.
Recommendation
Immediately upgrade Traefik to version v2.11.51, v3.6.22, or v3.7.6, depending on the branch in use, to remediate the vulnerability.
Original NVD description (English source)
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.