CVE-2026-87853
Sssd: sssd: idp authentication prefix comparison allows cross-user impersonation
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-187 |
| Vendor | red hat |
| Product | red hat enterprise linux 10 |
| Published | Sep 9, 2026 |
| Last Updated | Sep 10, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Affected Versions
Red Hat / Red Hat Enterprise Linux 10
All versions affected Red Hat / Red Hat Enterprise Linux 6
All versions affected Red Hat / Red Hat Enterprise Linux 7
All versions affected Red Hat / Red Hat Enterprise Linux 8
All versions affected Red Hat / Red Hat Enterprise Linux 9
All versions affected Red Hat / Red Hat OpenShift Container Platform 4
All versions affected Red Hat / Red Hat OpenShift Container Platform 4
All versions affected References
Credits
Red Hat would like to thank Moritz Theile for reporting this issue.