Bug 2510012 (CVE-2026-67309)

Summary: CVE-2026-67309 github.com/traefik/traefik: Traefik: Authentication bypass via path traversal in RewriteTarget middleware
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: urgent Docs Contact:
Priority: urgent    
Version: unspecifiedCC: anjoseph, jprabhak, sdawley, wtam
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Traefik. This path traversal vulnerability exists in the Kubernetes Ingress NGINX provider's RewriteTarget middleware. A remote attacker can craft a special request that uses dot-segment traversal to bypass authentication mechanisms like BasicAuth, DigestAuth, or ForwardAuth. This allows access to otherwise protected administrative endpoints.
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Description OSIDB Bzimport 2026-08-01 13:03:15 UTC 
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.