Flat PHP Board 1.2 and earlier stores sensitive information under the web root with insufficient access control, which allows remote attackers to obtain credentials via a direct request for the username php file for any user account in users/.

Multiple directory traversal vulnerabilities in index.php in Flat PHP Board 1.2 and earlier allow remote attackers to (1) create arbitrary files via a .. (dot dot) in the username parameter when registering a user account, and (2) read arbitrary PHP files via a .. (dot dot) in (a) the topic parameter in a topic action or (b) the username parameter in a viewprofile action.

Flat PHP Board 1.2 and earlier allows remote attackers to bypass authentication and obtain limited access to an arbitrary user account via the fpb_username cookie.