phpMyFAQ 4.2.0-alpha before 4.2.0-beta Account Takeover via Keycloak Implicit Account Linking

phpMyFAQ 4.2.0-alpha before 4.2.0-beta contains an authentication bypass vulnerability that allows Keycloak users to take over local accounts by matching preferred_username or email. Attackers controlling a Keycloak identity with a colliding username or unverified email can log in through /auth/keycloak/authorize to bind their subject and gain superadmin privileges.