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Thu, 10 Sep 2026 15:30:00 +0000
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ssvc
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Thu, 10 Sep 2026 13:30:00 +0000
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| Description | Traefik is an HTTP reverse proxy and load balancer. In Traefik v1.x, v2.x through v2.11.55, and v3.0.0 through v3.7.11, header names are canonicalized only on dashes, so X-Auth-User, X_Auth_User and X.Auth.User are treated as three distinct headers by Traefik, while backends that derive variable names from header names (CGI, WSGI, PHP, NGINX and others) collapse them into a single variable. A client can therefore smuggle a dot-form alias of a header that Traefik manages past the middleware managing it — for example supplying X.Authenticated.User alongside the canonical X-Authenticated-User written by the ForwardAuth middleware — causing such a backend to read the client-supplied value instead of the identity Traefik asserted. In the tested configuration (PHP 8.2 built-in SAPI over an HTTP/1 backend path), Go's lexical header ordering makes the attacker-supplied value win deterministically, so a client that ForwardAuth admits as a low-privilege identity can be treated by the backend as a different user or role. Any header Traefik sets is affected, not only ForwardAuth's. This is an incomplete fix for GHSA-x677-9fxg-v5c5, which blocked only the underscore form. Fixed in v2.11.56 and v3.7.12, which add the aliasHeadersStrategy entry-point option; because it defaults to 'keep' for backwards compatibility, it must be explicitly set to 'delete' or 'reject' for the fix to take effect. Unmaintained release lines will not receive a patch. | |
| Title | Traefik before v2.11.56 Identity Spoofing via Header Alias | |
| First Time appeared |
Traefik
Traefik traefik |
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| Weaknesses | CWE-290 | |
| CPEs | cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Traefik
Traefik traefik |
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| References |
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| Metrics |
cvssV4_0
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Projects
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Status: PUBLISHED
Assigner: VulnCheck
Published:
Updated: 2026-09-10T15:04:00.316Z
Reserved: 2026-09-10T11:24:26.196Z
Link: CVE-2026-88879
Updated: 2026-09-10T15:03:41.162Z
Status : Awaiting Analysis
Published: 2026-09-10T14:17:16.337
Modified: 2026-09-10T16:18:11.383
Link: CVE-2026-88879
No data.
OpenCVE Enrichment
Updated: 2026-09-10T15:00:15Z