usercp_avatar.php in PHPBB 2.0.20, when avatar uploading is enabled, allows remote attackers to use the server as a web proxy by submitting a URL to the avatarurl parameter, which is then used in an HTTP GET request.
PHP remote file inclusion vulnerability in /includes/kb_constants.php in Knowledge Base Mod for PHPbb 2.0.2 and earlier allows remote attackers to execute arbitrary PHP code via a URL in the module_root_path parameter.