CVE-2026-87853EPSS p39.0%
CVE-2026-87853CVE-2026-87853
Description
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.
Scoring
| CVSS | 7.5 () |
| Vector | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
| EPSS | 0.48% probability of exploitation · percentile 39.0% · 2026-10-05T12:00:23Z |
| Last modified | 2026-09-10 |