CVE-2026-87853Sssd: sssd: idp authentication prefix comparison allows cross-user impersonation
Updated under an hour ago ()
Does this affect you?
It affects Red Hat Enterprise Linux 10 and 1 other product. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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Free account, 1 product
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 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-187
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- redhat
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 8, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Red Hat Red Hat Enterprise Linux 10 redhat:enterprise_linux | from 0:2.12.0-3.el10_2.2 not affected | CNA record |
Red Hat Red Hat OpenShift Container Platform 4 redhat:openshift | 4 | CNA record |
References
- https://access.redhat.com/errata/RHSA-2026:77534vendor-advisory, x-refsource-redhat
- https://access.redhat.com/security/cve/CVE-2026-87853vdb-entry, x-refsource-redhat
- https://bugzilla.redhat.com/show_bug.cgi?id=2530888issue-tracking, x-refsource-redhat
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.