phpMyFAQ 3.2.0 before 4.0.0 and 4.0.2 before 4.2.0-beta contains an authentication bypass in its Microsoft Entra ID login flow, which links users by the mutable preferred_username claim and whose AuthEntraId::create() ignores the duplicate-login exception while continuing with the existing local account. Attackers controlling an Entra identity in the configured tenant with a matching preferred_username can take over that local account, including super-admin accounts.

phpMyFAQ 3.2.0 before 4.0.0 and 4.0.2 before 4.2.0-beta contains an authentication bypass in its Microsoft Entra ID login flow, which links users by the mutable preferred_username claim and whose AuthEntraId::create() ignores the duplicate-login exception while continuing with the existing local account. Attackers controlling an Entra identity in the configured tenant with a matching preferred_username can take over that local account, including super-admin accounts.