{"id":"CVE-2026-87853","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-87853","summary":"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…","details":"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":"2026-09-09T17:17:52.827","modified":"2026-09-10T15:17:54.240","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":null,"references":[{"type":"WEB","url":"https://access.redhat.com/security/cve/CVE-2026-87853"},{"type":"WEB","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2530888"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-09-10T15:17:54.240"}}