index.php in Jelsoft vBulletin does not properly initialize a PHP variable that is used to store template information, which allows remote attackers to execute arbitrary PHP code via special characters in the templatecache parameter.
misc.php for vBulletin 3.0.6 and earlier, when "Add Template Name in HTML Comments" is enabled, allows remote attackers to execute arbitrary PHP code via nested variables in the template parameter.
Cross-site scripting (XSS) vulnerability in Jelsoft vBulletin before 3.0 allows remote attackers to inject arbitrary web script or HTML via the what parameter to memberlist.php.