A flaw was found in SSSD. When configured with the LDAP access provider and ldap_access_order including ppolicy or lockout, a fail-open condition in the LDAP ppolicy access check can occur if a user lookup returns zero results. This can incorrectly return success and cache an allow decision, permitting continued authorization for a deleted or deprovisioned user. A remote attacker with prior valid account context could exploit this to maintain access to information and potentially make limited modifications to resources that should no longer be available.
There's no available mitigation for this issue.