Vulnerability in Red Hat Enterprise Linux 10

[ Description ]Official 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.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• BSI CERT-Bund8 Oct 2026WID-SEC-2026-3848

  Red Hat Enterprise Linux (sssd, tftp, ansible-collection-ansible-posix): Multiple vulnerabilities Translated from German

  CVE-2026-11837CVE-2026-85234CVE-2026-87853

[ References ]References

• access.redhat.com/errata/RHSA-2026:77534vendor-advisoryx_refsource_REDHAT
• access.redhat.com/security/cve/CVE-2026-87853vdb-entryx_refsource_REDHAT
• bugzilla.redhat.com/show_bug.cgiissue-trackingx_refsource_REDHAT