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bdu:2026-05930

certfr-2026-avi-0366 — De multiples vulnérabilités ont été découvertes dans Traefik. Elles permettent à un attaquant de provoquer un contourne…

certfr-2026-avi-0366

Withdrawn: CLEANSTART-2026-QI45196 — Security fixes in forecastle 1.0.159-r1

Withdrawn by the publisher.

Affected: CleanStart: forecastle

Package forecastle version 1.0.159-r1 fixes 43 vulnerabilities: CVE-2026-40611, CVE-2026-34986, CVE-2026-48020, CVE-2026-26999, CVE-2026-29054...

EUVD-2026-337338

fkie_cve-2026-33433

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.

GHSA-qr99-7898-vr7c — Traefik Vulnerable to BasicAuth/DigestAuth Identity Spoofing via Non-Canonical headerField

Affected: Go: github.com/traefik/traefik/v2, Go: github.com/traefik/traefik/v3

## Summary

There is a potential vulnerability in Traefik's Basic and Digest authentication middlewares when `headerField` is configured with a non-canonical HTTP header name.

An authenticated attacker with valid credentials can inject the canonical version of the configured header to impersonate any identity to the backend. Because Traefik writes the authenticated username using a non-canonical map key, it creates a separate header entry rather than overwriting the attacker's canonical one — causing most backend frameworks to read the attacker-controlled value instead.

## Patches

- <https://github.com/traefik/traefik/releases/tag/v2.11.42> - <https://github.com/traefik/traefik/releases/tag/v3.6.12> - <https://github.com/traefik/traefik/releases/tag/v3.7.0-ea.3>

## For more information

If there are any questions or comments about this advisory, please [open an issue](https://github.com/traefik/traefik/issues).

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<details> <summary>Original Description</summary>

### Summary

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 a 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.

Tested on Traefik v3.6.10.

### Details

At `pkg/middlewares/auth/basic_auth.go:92`, the authenticated username is written using…

RHSA-2026:10175 — Red Hat Security Advisory: Red Hat OpenShift Dev Spaces 3.27.1 Release.

golang: archive/zip: Excessive CPU consumption when building archive index in archive/zip axios: Axios: Server-Side Request Forgery and proxy bypass due to improper hostname normalization org.eclipse.jetty/jetty-http: HTTP request smuggling via chunked extension quoted-string parsing lodash: lodash: Arbitrary code execution via untrusted input in template imports path-to-regexp: path-to-regexp: Denial of Service via crafted regular expressions Spring Boot: Spring Boot: Authentication bypass via misconfigured Health Group additional path net/url: Incorrect parsing of IPv6 host literals in net/url github.com/traefik/traefik: Traefik: Denial of Service due to incomplete TLS handshake crypto/x509: Incorrect enforcement of email constraints in crypto/x509 rollup: Rollup: Remote Code Execution via Path Traversal Vulnerability github.com/traefik/traefik: Traefik: Information disclosure due to case-insensitive Connection header processing Traefik: github.com/traefik/traefik: Traefik: mTLS bypass allows unauthorized service access via fragmented ClientHello. github.com/traefik/traefik: Traefik: Cross-tenant traffic exposure and host restriction bypass via rule-syntax injection in Knative provider google.golang.org/grpc/grpc-go: google.golang.org/grpc/authz: gRPC-Go: Authorization bypass due to improper HTTP/2 path validation github.com/traefik/traefik: Traefik: Authentication bypass via non-canonical HTTP header injection @fastify/reply-from: @fastify/http-proxy: Fastify Reply From a…