PHP-Nuke 5.x allows remote attackers to perform arbitrary SQL operations by modifying the "prefix" variable when calling any scripts that do not already define the prefix variable (e.g., by including mainfile.php), such as article.php.

banners.php in PHP-Nuke 4.4 and earlier allows remote attackers to modify banner ad URLs by directly calling the Change operation, which does not require authentication.

cookiedecode function in PHP-Nuke 4.4 allows users to bypass authentication and gain access to other user accounts by extracting the authentication information from a cookie.

opendir.php script in PHP-Nuke allows remote attackers to read arbitrary files by specifying the filename as an argument to the requesturl parameter.

bb_smilies.php and bbcode_ref.php in PHP-Nuke 4.4 allows remote attackers to read arbitrary files and gain PHP administrator privileges by inserting a null character and .. (dot dot) sequences into a malformed username argument.

PHP-Nuke 4.4.1a allows remote attackers to modify a user's email address and obtain the password by guessing the user id (UID) and calling user.php with the saveuser operator.

admin.php3 in PHP-Nuke does not properly verify the PHP-Nuke administrator password, which allows remote attackers to gain privileges by requesting a URL that does not specify the aid or pwd parameter.