CVE-2026-41174 Traefik Kubernetes CRD allows unauthorized cross-namespace middleware binding

What is CVE-2026-41174?

CVE-2026-41174 is a medium-severity missing authorization vulnerability in Traefik Traefik, published on 30 Apr 2026. It can only be exploited from the same machine or local network, 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 a potential vulnerability in Traefik's Kubernetes CRD provider cross-namespace isolation enforcement. When providers.kubernetesCRD.allowCrossNamespace=false, Traefik correctly rejects direct cross-namespace middleware references from IngressRoute objects, but fails to apply the same restriction to middleware references nested inside a Chain middleware's spec.chain.middlewares[]. An actor with permission to create or update Traefik CRDs in their own namespace can exploit this to cause Traefik to resolve and apply middleware objects from another namespace, bypassing the documented isolation boundary. This issue has been patched in versions 2.11.43, 3.6.14, and 3.7.0-rc.2.

Weakness: CWE-863, CWE-653

Which versions are affected by CVE-2026-41174?

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.

Products include Traefik Traefik.

How do I fix CVE-2026-41174?

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 check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-41174 being exploited?

There is no known exploitation of CVE-2026-41174 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 Critical 9.8
• CVE-2026-88877 Traefik v3.7.0 Authentication Bypass via from-to-www-redirect Critical 9.3
• CVE-2026-85595 Traefik before v2.11.55 and v3.0.0 through v3.7.10 Authentication Bypass via digestAuth Critical 9.3
• CVE-2026-88007 Traefik HTTP/3 Backend NTLM Connection Reuse Critical 9.1
• CVE-2026-88009 Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging High 8.8

All Traefik Traefik vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as CLEANSTART-2026-XS53606, GHSA-xhjw-95fp-8vgq, GO-2026-5760, MINI-2x49-ccwm-8gvq, MINI-4c5v-x5w2-g27w, MINI-c5gx-9crm-5778.