The remote host is vulnerable to a flaw that allows for the bypassing of authentication.
The remote host is running phpBB, a web-based forum application written in PHP. There is a flaw in this version of phpBB that will allow a remote attacker to bypass the login process. Specifically, a malformed cookie, when processed by phpBB, will always result in a 'true' value.
Upgrade to version 2.0.13 or higher.