CVE-2026-87853
High
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.
SeverityHigh
CVSS7.5
Exploit probability—
Product
Red Hat Enterprise Linux 10
PublishedSep 9, 2026
First seenSep 9, 2026
Weakness typeCWE-187CWE-187
How to fix
Vendor advisories
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Red Hat Red Hat Enterprise Linux 10 | No range specified | — |
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