CVE-2026-92821

A flaw was found in SSSD. When configured to evaluate password expiration warnings before restrictive access rules in LDAP (Lightweight Directory Access Protocol) environments, an expired-password warning terminates rule evaluation early and treats the access request as successful. A remote authenticated user with an expired password using an alternative authentication method, such as SSH public key authentication, can exploit this flaw to bypass access control restrictions and gain unauthorized access to protected systems.

This vulnerability is rated as Moderate severity because successful exploitation requires a specific non-default configuration where pwd_expire_policy_warn is ordered ahead of restrictive rules in ldap_access_order, combined with a valid user account possessing an expired password. In default Red Hat Enterprise Linux configurations, this access evaluation sequence is not configured, which minimizes typical exposure. While the flaw permits an authenticated user to bypass host or filter restrictions using alternate authentication methods such as SSH public keys, the prerequisites prevent remote, unauthenticated access or compromise in standard installations.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

The exposure can be removed by reordering the SSSD LDAP access rules without waiting for a package update. In the affected domain section of /etc/sssd/sssd.conf, set ldap_access_order so that restrictive rules such as filter, host, and rhost are evaluated before pwd_expire_policy_warn (for example, change ldap_access_order = pwd_expire_policy_warn, filter, host to ldap_access_order = filter, host, pwd_expire_policy_warn). Alternatively, replace pwd_expire_policy_warn with pwd_expire_policy_reject where accounts with expired passwords should not continue through the access chain. Restart the SSSD service (systemctl restart sssd) to apply the change. Note that restarting SSSD briefly interrupts active authentication requests and identity lookups, and switching to pwd_expire_policy_reject changes behavior so that users with expired passwords are denied instead of warned.