Traefik up to 3.7.7 RewriteTarget Middleware path traversal

Summaryinfo

A vulnerability labeled as critical has been found in Traefik up to 3.7.7. Affected by this issue is some unknown functionality of the component RewriteTarget Middleware. Executing a manipulation can lead to path traversal. This vulnerability is handled as CVE-2026-67309. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability has been found in Traefik up to 3.7.7 and classified as critical. This vulnerability affects an unknown part of the component RewriteTarget Middleware. The manipulation with an unknown input leads to a path traversal vulnerability. The CWE definition for the vulnerability is CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

Traefik versions >= v3.7.0 and <= v3.7.7 contain a path traversal vulnerability in the Kubernetes Ingress NGINX provider's RewriteTarget middleware (generated from the nginx.ingress.kubernetes.io/rewrite-target annotation). When an Ingress path uses a regex that captures attacker-controlled text without requiring a path separator (e.g., path /api(.*) with rewrite target /$1), a crafted request such as /api../admin matches the public router, is rewritten to a dot-segment traversal path (/../admin), and is forwarded without post-replacement normalization validation. A backend that normalizes dot segments resolves the path to a protected endpoint (e.g., /admin) reachable only through a separate router secured with BasicAuth, DigestAuth, or ForwardAuth, resulting in route-level authentication bypass. The issue is fixed in v3.7.8.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-67309 since 07/29/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1006.

Upgrading to version 3.7.8 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-51815). Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

• Traefik

Version

• 3.7.0
• 3.7.1
• 3.7.2
• 3.7.3
• 3.7.4
• 3.7.5
• 3.7.6
• 3.7.7

Website

• Product: https://github.com/traefik/traefik/

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Once again VulDB remains the best source for vulnerability data.

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