Bug 2506097 (CVE-2026-65600)

Summary: CVE-2026-65600 traefik: Traefik: Authentication bypass via path traversal in ReplacePathRegex middleware
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: urgent Docs Contact:
Priority: urgent    
Version: unspecifiedCC: sdawley
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Traefik. An unauthenticated remote attacker can bypass authentication due to a path traversal vulnerability in the ReplacePathRegex middleware. When this middleware is misconfigured, it forwards un-normalized paths, allowing a backend to resolve them to protected routes and grant unauthorized access. This bypass enables access to sensitive administrative interfaces.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-07-22 12:02:31 UTC 
Traefik versions <= v2.11.51, >= v3.6.0 <= v3.6.22, and >= v3.7.0 <= v3.7.6 contain an authentication bypass via path traversal in the ReplacePathRegex middleware. When ReplacePathRegex is configured with a regex that captures user-controlled path segments without a mandatory path separator (e.g. regex "^/api(.*)", replacement "/$1"), the middleware forwards the replaced path to the backend without validating that it matches its normalized form. An unauthenticated remote attacker can send a crafted request (e.g. GET /api../admin) that produces an un-normalized path such as /../admin, which a backend that normalizes paths resolves to a protected route, bypassing authentication middleware. Fixed in v2.11.52, v3.6.23, and v3.7.7.