TNCVE-2026-33433 | Vulnetix

TNCVE-2026-33433 PUBLISHED

Record from tenable · Published March 27, 2026

Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.42, 3.6.11, and 3.7.0-ea.3, when `headerField` is configured with a non-canonical HTTP header name (e.g., `x-auth-user` instead of `X-Auth-User`), an authenticated attacker can inject their own canonical version of that header to impersonate any identity to the backend. The backend receives two header entries — the attacker-injected canonical one is read first, overriding Traefik's non-canonical write. Versions 2.11.42, 3.6.11, and 3.7.0-ea.3 patch the issue.

Timeline

Mar 27, 2026 CVE Published

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vulnetix vdb vuln TNCVE-2026-33433
vulnetix vdb fixes TNCVE-2026-33433

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References

Tenable: CVE-2026-33433 advisory

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