CVE-2026-35051 Traefik: ForwardAuth trustForwardHeader=false allows spoofed X-Forwarded-Prefix to bypass auth
Attackers can bypass authentication in Traefik's ForwardAuth middleware by spoofing the X-Forwarded-Prefix header when trustForwardHeader is disabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-35051?
CVE-2026-35051 is a high-severity authentication bypass vulnerability in Traefik Traefik, published on 30 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-35051?
11 open source packages ship an affected version, including github.com/traefik/traefik/v3, github.com/traefik/traefik and github.com/traefik/traefik/v2. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/traefik/traefik/v3 Go | From 3.0.0-beta1 | 3.6.14, 3.7.0-rc.2 |
github.com/traefik/traefik/v3 Go | From 3.0.0-beta1 | 3.6.14 |
github.com/traefik/traefik/v3 Go | From 3.0.0-beta1 | 3.6.14 |
github.com/traefik/traefik/v3 Go | From 3.7.0-ea.1 | 3.7.0-rc.2 |
github.com/traefik/traefik/v3 Go | From 3.7.0-ea.1 | 3.7.0-rc.2 |
github.com/traefik/traefik Go | All versions | None |
5 more packages
github.com/traefik/traefik Go | All versions to 1.7.34 | None |
github.com/traefik/traefik Go | All versions to 1.7.34 | None |
github.com/traefik/traefik/v2 Go | All versions | 2.11.43 |
github.com/traefik/traefik/v2 Go | All versions | 2.11.43 |
github.com/traefik/traefik/v2 Go | All versions | 2.11.43 |
Products include Traefik Traefik.
How do I fix CVE-2026-35051?
Upgrade github.com/traefik/traefik/v3 to a fixed version for your release line: 3.6.14 or 3.7.0-rc.2.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-35051 being exploited?
There is no known exploitation of CVE-2026-35051 in the wild and no public exploit code.
Other vulnerabilities in Traefik Traefik
- CVE-2024-45410 HTTP client can remove the X-Forwarded headers in Traefik
- CVE-2026-88877 Traefik v3.7.0 Authentication Bypass via from-to-www-redirect
- CVE-2026-85595 Traefik before v2.11.55 and v3.0.0 through v3.7.10 Authentication Bypass via digestAuth
- CVE-2026-88007 Traefik HTTP/3 Backend NTLM Connection Reuse
- CVE-2026-88009 Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging
Sources
Also known as CLEANSTART-2026-FI72470, GHSA-6384-m2mw-rf54, GO-2026-5163, MINI-77cq-87hf-gqm2, MINI-cwwf-vpjw-pw79, MINI-v73c-4p97-jpjg.