Incomplete blacklist vulnerability in the stripScripts function in common.php in OneOrZero Helpdesk 1.6.5.4, 1.6.4.2, and possibly other versions, allows remote attackers to conduct cross-site scripting (XSS) attacks and inject arbitrary web script or HTML via XSS sequences without SCRIPT tags in the description parameter to (1) tcreate.php or (2) tupdate.php, as demonstrated using an onmouseover event in a b tag.