SQL injection vulnerability in PHP-Nuke 6.9 and earlier, and possibly 7.x, allows remote attackers to inject arbitrary SQL code and gain sensitive information via (1) the category variable in the Search module or (2) the admin variable in the Web_Links module.

sql_layer.php in PHP-Nuke 5.4 and earlier does not restrict access to debugging features, which allows remote attackers to gain SQL query information by setting the sql_debug parameter to (1) index.php and (2) modules.php.

index.php in Francisco Burzi PHP-Nuke 5.3.1 and earlier, and possibly other versions before 5.5, allows remote attackers to execute arbitrary PHP code by specifying a URL to the malicious code in the file parameter.

Cross-site scripting (XSS) vulnerability in PHP-Nuke 5.3.1 and earlier allows remote attackers to inject arbitrary web script or HTML via the (1) uname parameter in user.php, (2) ttitle, letter and file parameters in modules.php, (3) subject, story and storyext parameters in submit.php, (4) upload parameter in admin.php and (5) fname parameter in friend.php.

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.

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.