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OpenAdvisories
Medium · 6.9 CVE-2026-54764 EUVD-2026-41937GHSA-3q9r-p662-5j8mGO-2026-6202

ForwardAuth middleware leaks X-Forwarded-Port spoofing via untrusted X-Forwarded-Proto when trustForwardHeader=false

Published Jul 6, 2026 · Updated Jul 7, 2026 · Assigned by GitHub_M

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

VendorProductAffectedFixed
traefik traefik < 2.11.51, >= 3.0.0, < 3.6.22, >= 3.7.0, < 3.7.6 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
SLES for SAP 16.0 govulncheck-vulndb 0.0.20260827T195228-160000.1.1 SUSE-SU-2026:23625-1
SLES 16.0 govulncheck-vulndb 0.0.20260827T195228-160000.1.1 SUSE-SU-2026:23625-1
ReleasePackageFixed inAdvisory
openSUSE Tumbleweed traefik 3.7.7-1.1 openSUSE-SU-2026:11251-1
openSUSE Tumbleweed traefik2 2.11.52-1.1 openSUSE-SU-2026:11243-1
openSUSE Leap 16.0 govulncheck-vulndb 0.0.20260827T195228-160000.1.1 openSUSE-SU-2026:21761-1

Affected packages

EcosystemPackageAffectedFixedRecord
Go github.com/traefik/traefik <= 1.7.34 — GHSA-3q9r-p662-5j8m
Go github.com/traefik/traefik all versions — GO-2026-6202
Go github.com/traefik/traefik/v2 < 2.11.51 2.11.51 GHSA-3q9r-p662-5j8m
Go github.com/traefik/traefik/v3 < 3.6.22 3.6.22 GHSA-3q9r-p662-5j8m
Go github.com/traefik/traefik/v3 >= 3.7.0, < 3.7.6 3.7.6 GHSA-3q9r-p662-5j8m
Go github.com/traefik/traefik/v3 < 3.6.22 · >= 3.7.0, < 3.7.6 3.6.22, 3.7.6 GO-2026-6202

Advisories 4

References