CVE catalog
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` inste
- Severity
- High · CVSS 7.7
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:N - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.49% · Oct 25, 2026
A flaw was found in Traefik, an HTTP reverse proxy and load balancer. When the `headerField` is configured with a non-canonical HTTP header name, an authenticated attacker can inject a canonical version of that header. This allows the attacker to impersonate any identity to the backend, leading to an authentication bypass. The backend prioritizes the attacker-injected header, overriding Traefik's intended header. github.com/traefik/traefik: Traefik: Authentication bypass via non-canonical HTTP header injection The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Cpe | traefik | Not reported | 2.11.42 | fixed |
| Cpe | traefik | Not reported | 3.6.12 | fixed |
| Cpe | traefik | Not reported | Not reported | unknown |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Cpe | traefik | cpe | Not reported | 2.11.42 | Not reported | Not reported | Not reported |
| Cpe | traefik | cpe | Not reported | 3.6.12 | Not reported | Not reported | Not reported |
OpenFactory catalog packages
No matching packages in this catalog.
Observed: