Cross-site request forgery (CSRF) vulnerability in phpBB 2.0.19, when Link to off-site Avatar or bbcode (IMG) are enabled, allows remote attackers to perform unauthorized actions as a logged in user via a link or IMG tag in a user profile, as demonstrated using links to (1) admin/admin_users.php and (2) modcp.php.

Multiple SQL injection vulnerabilities in phpbb-Auction allow remote attackers to execute arbitrary SQL commands via the (1) u parameter to auction_rating.php or (2) ar parameter to action_offer.php.

Directory traversal vulnerability in (1) usercp_register.php and (2) usercp_avatar.php for phpBB 2.0.11, and possibly other versions, with gallery avatars enabled, allows remote attackers to delete (unlink) arbitrary files via "/../" sequences in the avatarselect parameter.

CRLF injection vulnerability in PhpBB 2.0.4 and 2.0.9 allows remote attackers to perform HTTP Response Splitting attacks to modify expected HTML content from the server via (1) the mode parameter to privmsg.php or (2) the redirect parameter to login.php.

phpBB 2.0.8a and earlier trusts the IP address that is in the X-Forwarded-For in the HTTP header, which allows remote attackers to spoof IP addresses.

install.php in phpBB 2.0 through 2.0.1, when "allow_url_fopen" and "register_globals" variables are set to "on", allows remote attackers to execute arbitrary PHP code by modifying the phpbb_root_dir parameter to reference a URL on a remote web server that contains the code.