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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
High
Admin privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
Vulnerable Products 4
| Configuration | From (including) | Up to (excluding) |
|---|---|---|
|
Traefik Traefik
cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*
|
— |
2.11.42
|
|
Traefik Traefik
cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*
|
3.0.0
|
3.6.12
|
|
Traefik Traefik
cpe:2.3:a:traefik:traefik:3.7.0:ea1:*:*:*:*:*:*
|
— | — |
|
Traefik Traefik
cpe:2.3:a:traefik:traefik:3.7.0:ea2:*:*:*:*:*:*
|
— | — |
References 4
https://github.com/traefik/traefik/releases/tag/v2.11.42
security-advisories@github.com
https://github.com/traefik/traefik/releases/tag/v3.6.11
security-advisories@github.com
https://github.com/traefik/traefik/releases/tag/v3.7.0-ea.3
security-advisories@github.com
https://github.com/traefik/traefik/security/advisories/GHSA-qr99-7898-vr7c
security-advisories@github.com