Disclosure 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 an exact match. An attacker whose IdP identifier is a strict prefix of a target user's identifier can authenticate as the target user.
Source-reported weakness categories
CWE-187
Source-specific records & product guidance
Sources retain their own attribution and scoring. Follow the original record to confirm affected versions, fixed releases, and configuration conditions.
LinuxSecurity Advisories - Oracle · RSS-721d3654e9f06c3abccc8c5c1149e4132c6
Open original source · Updated Oct 09, 2026
Oracle Linux 10 sssd Moderate CVE-2026-87853 Advisory ELSA-2026-77534
CVE mention in publisher metadata; check the original affected versions.
NIST National Vulnerability Database · NVD-CVE-2026-87853
Open original source · Updated Oct 08, 2026
Only CPE matches marked vulnerable=true are indexed. AND/OR platform conditions must be checked in the original NVD record.
Original records & references
PUBLISHED 2026-09-09T13:17:52-04:00
MODIFIED 2026-10-08T20:17:09-04:00
INGESTED 2026-10-10T20:50:44-04:00