CVE-2026-35051 PUBLISHED

Traefik: ForwardAuth trustForwardHeader=false allows spoofed X-Forwarded-Prefix to bypass auth

Assigner: GitHub_M
Reserved: 31.03.2026 Published: 30.04.2026 Updated: 30.04.2026

Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is an authentication bypass vulnerability in Traefik's ForwardAuth middleware when trustForwardHeader=false is configured and Traefik is deployed behind a trusted upstream proxy. This issue has been patched in versions 2.11.43, 3.6.14, and 3.7.0-rc.2.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N
CVSS Score: 7.8

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	High
Attack Complexity	Low	Integrity	None	Integrity	Low
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	traefik
Product	traefik
Versions	Version < 2.11.43 is affected Version >= 3.0.0-beta1, < 3.6.14 is affected Version >= 3.7.0-ea.1, < 3.7.0-rc.2 is affected

References

Problem Types

CWE-345: Insufficient Verification of Data Authenticity CWE