source: https://www.securityfocus.com/bid/13303/info
PayProCart is prone to a cross-site scripting vulnerability. This issue is due to a failure in the application to properly sanitize user-supplied input.
An attacker may leverage this issue to have arbitrary script code executed in the browser of an unsuspecting user. This may facilitate the theft of cookie-based authentication credentials as well as other attacks.
http://www.example.com/path_to_store/cart.php?chckoutaction=1&ckprvd=%22%3E%3Cscript%3Ealert(document.cookie)%3C/script%3E
