The vulnerability CVE-2026-46579 exists in the OpenShift Router component of Red Hat OpenShift Container Platform. Specifically, when the Route resource has the insecureEdgeTerminationPolicy set to Allow, the HTTP frontend does not strip the X-SSL-Client-* headers from incoming HTTP requests. These headers are normally used to convey client certificate information in mutual TLS authentication. Because the headers are not removed, an unauthenticated attacker can craft HTTP requests with arbitrary X-SSL-Client-* headers to impersonate client certificate identities, effectively bypassing mutual TLS authentication mechanisms that rely on these headers. This is classified as an improper authentication vulnerability (CWE-287) with a CVSS 3.1 base score of 7.4 (high severity), reflecting network attack vector, high complexity, no privileges required, no user interaction, and high impact on confidentiality and integrity but no impact on availability. Red Hat has issued security advisories RHSA-2026:27009 and RHSA-2026:27044 providing updated container images and packages for OpenShift Container Platform 4.22.2 and 4.21.21 respectively, which include fixes for this vulnerability. The advisories include instructions for upgrading clusters and inspecting release image metadata. No known exploits in the wild have been reported at this time.

An unauthenticated attacker can bypass mutual TLS authentication by sending crafted HTTP requests with X-SSL-Client-* headers when insecureEdgeTerminationPolicy is set to Allow on a Route. This allows the attacker to impersonate client certificate identities, potentially gaining unauthorized access to backend services that rely on these headers for authentication. The vulnerability impacts confidentiality and integrity of the system but does not affect availability. No known active exploitation has been reported.

Red Hat has released official security updates fixing this vulnerability in OpenShift Container Platform versions 4.21.21 and 4.22.2. Users should upgrade their clusters to these versions or later as soon as they become available through the appropriate release channels. Instructions for upgrading are provided in the Red Hat OpenShift documentation. There is no indication from the vendor advisory that additional temporary mitigations or workarounds are required beyond applying the official updates.