CVE-2026-87853: Red Hat Enterprise Linux 10

High severity, CVSS 7.5. EPSS: 0.3% chance of exploitation in the next 30 days.

A flaw was found in SSSD's IdP authentication provider. The eval_access_token_buf() function compares the OIDC subject identifier using strncmp() with the authenticated user's identifier length, performing a prefix comparison instead of an exact match. An attacker whose IdP identifier is a strict prefix of a target user's identifier can authenticate as the target user.

Affected products

• Red Hat Red Hat Enterprise Linux 10: before 0:2.12.0-3.el10_2.2 (fixed in 0:2.12.0-3.el10_2.2)
• Red Hat Red Hat Enterprise Linux 6
• Red Hat Red Hat Enterprise Linux 7
• Red Hat Red Hat Enterprise Linux 8
• Red Hat Red Hat Enterprise Linux 9
• Red Hat Red Hat Openshift Container Platform 4

Published 2026-09-09. Last modified 2026-10-09.