Cross-namespace policy bypass via nested middleware resolution
Published Apr 30, 2026 · Updated Apr 30, 2026
Authorization bypass in Traefik Proxy before 2.11.43, 3.6.14, and 3.7.0-rc.2 allows local users to bind cross-namespace middleware. The Kubernetes CRD provider's createChainMiddleware path resolves spec.chain.middlewares[].namespace unconditionally instead of enforcing allowCrossNamespace=false. Exploitation requires permission to create or update Traefik CRDs in one namespace and permits reuse of policy-bearing middleware from another namespace.
Summary
What happened
Authorization bypass in Traefik Proxy before 2.11.43, 3.6.14, and 3.7.0-rc.2 allows local users to bind cross-namespace middleware. The Kubernetes CRD provider's createChainMiddleware path resolves spec.chain.middlewares[].namespace unconditionally instead of enforcing allowCrossNamespace=false. Exploitation requires permission to create or update Traefik CRDs in one namespace and permits reuse of policy-bearing middleware from another namespace.
The record
- CVE
- CVE-2026-41174
- Published
- Apr 30, 2026
- Updated
- Apr 30, 2026
- Vendor
- Traefik Labs
- Product
- Traefik Proxy
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 30, 2026CVE publishedPublication date reported by the CVE source.
- Apr 30, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 2.11.43
- Affected versionversion=>= 3.7.0-ea.1, < 3.7.0-rc.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
No sourced classifications are available.
Public exploit references
- Upstream nested Chain middleware proof of conceptproof of concept · demonstrated
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Technologies
Your stack
See the directory against your own environment.
Your stack
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