Denial of Service Vulnerability in Traefik HTTP Reverse Proxy and Load Balancer

CVE-2026-26998

What is CVE-2026-26998?

Traefik, a popular HTTP reverse proxy and load balancer, has a vulnerability associated with the ForwardAuth middleware. When configured to utilize this middleware, Traefik reads the entire response body from the authentication server without imposing any size limitations. This flaw allows for the possibility of receiving a response body that is excessively large or unbounded. As a result, Traefik could potentially allocate an unlimited amount of memory, leading to an out-of-memory (OOM) condition that may crash the service and disrupt all routes being served. The issue has been resolved in Traefik versions 2.11.38 and 3.6.9.

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