CVE-2026-87853
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.
- Published Sep 9, 2026
- CVSS 7.5 high
- 0.5% chance of exploitation in the next 30 days (EPSS)