CVE-2026-22797 is a privilege escalation vulnerability in the external_oauth2_token middleware component of OpenStack keystonemiddleware, which is part of Red Hat OpenShift Container Platform. The flaw arises because the middleware does not correctly sanitize incoming authentication headers, enabling an authenticated attacker to send forged identity headers (e.g., X-Is-Admin-Project, X-Roles, X-User-Id). Exploiting this flaw can allow attackers to escalate privileges or impersonate other users. Red Hat has rated this vulnerability as Important and assigned a CVSS v3 base score of 9.9, indicating high severity. The fix is included in OpenShift Container Platform 4.21.4, which contains updated container images and packages. Users are advised to upgrade to this release to mitigate the vulnerability.

An authenticated attacker can exploit this vulnerability to escalate privileges or impersonate other users by sending forged authentication headers. This compromises access control and authentication mechanisms, potentially allowing unauthorized access to sensitive resources within Red Hat OpenShift Container Platform deployments that use the affected middleware. The vulnerability affects confidentiality, integrity, and to a lesser extent availability, with a high impact on confidentiality and integrity.

Red Hat has released OpenShift Container Platform version 4.21.4 containing fixes for this vulnerability. Users should upgrade to version 4.21.4 or later as soon as possible using the official upgrade documentation. The vendor advisory confirms the availability of an official fix. No alternative mitigations are specified. Users should follow Red Hat's upgrade instructions to fully apply the update and remediate the issue.