Unspecified vulnerability in phpBB before 2.0.22 has unknown impact and remote attack vectors related to "criteria for 'bad' redirection targets."
http://www.securityfocus.com/bid/21806
http://www.phpbb.com/phpBB/viewtopic.php?f=14&t=489624
http://www.debian.org/security/2008/dsa-1488