An issue was discovered in OpenStack keystonemiddleware 10.5 through 10.7 before 10.7.2, 10.8 and 10.9 before 10.9.1, and 10.10 through 10.12 before 10.12.1. The external_oauth2_token middleware fails to sanitize incoming authentication headers before processing OAuth 2.0 tokens. By sending forged identity headers such as X-Is-Admin-Project, X-Roles, or X-User-Id, an authenticated attacker may escalate privileges or impersonate other users. All deployments using the external_oauth2_token middleware are affected.
https://www.openwall.com/lists/oss-security/2026/01/16/9
https://launchpad.net/bugs/2129018
http://www.openwall.com/lists/oss-security/2026/01/16/9
http://www.openwall.com/lists/oss-security/2026/01/16/3