REDHAT-BUG-2452289: High severity Traefik traefik vulnerability

Published Mar 27, 2026
·
Updated

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.

Affected Software

1 affected component
Traefik traefik<2.11.42, <3.6.11, <3.7.0-ea.3

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 2.11.42
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 3.6.11
  3. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 3.7.0-ea.3

Event History

Mar 27, 2026
Data Sourced
via Red Hat·03:03 PM
DescriptionSeverityAffected Software
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Frequently Asked Questions

1

What is the severity of REDHAT-BUG-2452289?

The severity of REDHAT-BUG-2452289 is high, rated at 7.

2

How do I fix REDHAT-BUG-2452289?

To fix REDHAT-BUG-2452289, upgrade Traefik to versions 2.11.42, 3.6.11, or 3.7.0-ea.3 or later.

3

What vulnerability does REDHAT-BUG-2452289 describe?

REDHAT-BUG-2452289 describes a vulnerability that allows an authenticated attacker to inject a canonical version of a non-canonical HTTP header name.

4

Which versions of Traefik are affected by REDHAT-BUG-2452289?

Traefik versions prior to 2.11.42, 3.6.11, and 3.7.0-ea.3 are affected by REDHAT-BUG-2452289.

5

What potential impact does REDHAT-BUG-2452289 have?

The potential impact of REDHAT-BUG-2452289 is unauthorized header injection by authenticated attackers.

Contact

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