Cross-site scripting (XSS) vulnerability in ppcal.cgi in PPCal Shopping Cart 3.3.0 and earlier allows remote attackers to inject arbitrary web script or HTML via the (1) stop and (2) user parameters.
http://www.vupen.com/english/advisories/2005/2918
http://secunia.com/advisories/18032
http://pridels0.blogspot.com/2005/12/ppcal-shopping-cart-xss.html