{"id":"CVE-2026-87853","title":"A flaw was found in SSSD's IdP authentication provider","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 length, performing a prefix comparison instead of …","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-187"],"vendor":"Red Hat","product":"sssd","affected":["sssd (all versions)","sssd","sssd","sssd","sssd","openshift/ose-rhel-coreos-8","openshift/ose-rhel-coreos-9"],"published":"2026-09-09","updated":"2026-09-10","sourceUpdated":"2026-09-10T15:17:54.240","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-87853","references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-87853","label":"secalert@redhat.com"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2530888","label":"secalert@redhat.com"}],"tags":["nvd","cve.org"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-09-09T18:28:46.606582Z"},"ingestedAt":"2026-09-13T05:23:50.971Z","epss":0.00477,"epssPercentile":0.38523,"slug":"CVE-2026-87853","body":"## Overview\n\nA 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}