System Security Services Daemon (SSSD) before 1.0.1, when the krb5 auth_provider is configured but the KDC is unreachable, allows physically proximate attackers to authenticate, via an arbitrary password, to the screen-locking program on a workstation that has any user's Kerberos ticket-granting ticket (TGT); and might allow remote attackers to bypass intended access restrictions via vectors involving an arbitrary password in conjunction with a valid TGT.
CWE-287 - Improper Authentication
Improper (or broken) authentication attacks are widespread, and have accounted for many of the worst data breaches in recent years. Improper authentication attacks are a class of vulnerabilities where an attacker impersonates a legitimate user by exploiting weaknesses in either session management or credential management to gain access to the user’s account. This can result in disclosure of sensitive information, and can lead to system compromise, theft, identity theft, and fraud.