CVE-2026-35051

Modified Modified - Updated After Analysis

Authentication Bypass in Traefik Reverse Proxy

Publication date: 2026-04-30

Last updated on: 2026-06-30

Assigner: GitHub, Inc.

Description

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.

CVSS Scores

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Meta Information

Published

2026-04-30

Last Modified

2026-06-30

Generated

2026-07-06

AI Q&A

2026-05-01

EPSS Evaluated

2026-07-05

NVD

CVE-2026-35051

Affected Vendors & Products

Vendor	Product	Version / Range
traefik	traefik	3.7.0
traefik	traefik	3.7.0
traefik	traefik	to 2.11.43 (exc)
traefik	traefik	From 3.0.0 (inc) to 3.6.14 (exc)
traefik	traefik	3.7.0
traefik	traefik	3.7.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-501	The product mixes trusted and untrusted data in the same data structure or structured message.
CWE-345	The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.

Attack-Flow Graph

Executive Summary

This vulnerability is an authentication bypass issue in Traefik's ForwardAuth middleware. It occurs when the configuration option trustForwardHeader is set to false and Traefik is deployed behind a trusted upstream proxy. This means that under these conditions, unauthorized users might bypass authentication checks.

Impact Analysis

The impact of this vulnerability is that attackers could potentially access protected resources without proper authentication. This could lead to unauthorized access to sensitive data or services that are supposed to be secured by Traefik's authentication mechanisms.

Mitigation Strategies

To mitigate this vulnerability, you should upgrade Traefik to one of the patched versions: 2.11.43, 3.6.14, or 3.7.0-rc.2.

Additionally, review your ForwardAuth middleware configuration, especially the trustForwardHeader setting, and ensure it is properly configured when Traefik is deployed behind a trusted upstream proxy.

Compliance Impact

The vulnerability is an authentication bypass in Traefik's ForwardAuth middleware when certain configurations are used. Such an authentication bypass could potentially allow unauthorized access to protected resources.

Unauthorized access due to this vulnerability may lead to non-compliance with standards and regulations like GDPR and HIPAA, which require strict access controls and protection of sensitive data.

However, the provided information does not explicitly describe the impact on compliance with these standards.

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