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.

member2.php in vBulletin 2.2.9 and earlier does not properly restrict the $perpage variable to be an integer, which causes an error message to be reflected back to the user without quoting, which facilitates cross-site scripting (XSS) and possibly other attacks.