CVE-2026-87853
highA flaw was found in SSSD's IdP authentication provider.
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.
CVSS
7.5
7.5 (CVSS v3.1)
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H Severity source: NVD CVSS v3.1 (secalert@redhat.com)
Timeline (UTC)
Published: 2026-09-09 17:17
Modified: 2026-10-21 19:17
NVD status: Awaiting Analysis
Last synced 1 day ago
Verified against the source API 2026-10-27 06:52 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).
Affected products
Not reported by the source (unknown — not "none").
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://access.redhat.com/errata/RHSA-2026:77534 secalert@redhat.com
- https://access.redhat.com/security/cve/CVE-2026-87853 secalert@redhat.com
- https://bugzilla.redhat.com/show_bug.cgi?id=2530888 secalert@redhat.com
Data sources
NVD CVE API 2.0 — fetched 2026-10-27 06:52 UTC · record ↗