Traefik up to 3.7.4 Backend Service failing open

Summaryinfo

A vulnerability was found in Traefik up to 3.7.4. It has been classified as problematic. Affected is an unknown function of the component Backend Service. The manipulation leads to failing open. This vulnerability is referenced as CVE-2026-54762. The attack can only be performed from a local environment. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Traefik up to 3.7.4 and classified as problematic. This issue affects an unknown code block of the component Backend Service. The manipulation with an unknown input leads to a failing open vulnerability. Using CWE to declare the problem leads to CWE-636. When the product encounters an error condition or failure, its design requires it to fall back to a state that is less secure than other options that are available, such as selecting the weakest encryption algorithm or using the most permissive access control restrictions. Impacted is confidentiality. The summary by CVE is:

Traefik is an HTTP reverse proxy and load balancer. From 3.7.0-ea.1 until 3.7.5, there is a medium severity vulnerability in Traefik's Kubernetes Ingress NGINX provider that causes affected routes to fail open. When an Ingress explicitly enables BasicAuth or DigestAuth through the supported nginx.ingress.kubernetes.io/auth-type and auth-secret annotations, but the referenced auth Secret cannot be resolved or parsed, Traefik logs the resolution error, skips installing the authentication middleware, and still emits a router to the backend service. A route that operators intended to protect is therefore published to the data plane without its authentication control, allowing unauthenticated access to the backend. The trigger is an invalid or unresolved auth dependency — a missing, malformed, unreadable, or policy-denied Secret — rather than an intentionally unprotected route. This vulnerability is fixed in 3.7.5.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-54762 since 06/16/2026. The exploitation is known to be easy. An attack has to be approached locally. The exploitation requires an enhanced level of successful authentication. Neither technical details nor an exploit are publicly available.

Upgrading to version 3.7.5 eliminates this vulnerability. The upgrade is hosted for download at github.com.

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Productinfo

Name

• Traefik

Version

• 3.7.0
• 3.7.1
• 3.7.2
• 3.7.3
• 3.7.4

Website

• Product: https://github.com/traefik/traefik/

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