Cross-site scripting (XSS) vulnerability in PHP Handicapper allows remote attackers to inject arbitrary web script or HTML via the msg parameter to msg.php. NOTE: some sources identify a second vector in the login parameter to process_signup.php, but the original source says that it is for CRLF injection (CVE-2005-4712). Also note: the vendor has disputed CVE-2005-3497, and it is possible that the dispute was intended to include this issue as well. If so, followup investigation strongly suggests that the original report is correct.
http://www.zone-h.org/advisories/read/id=8360
http://www.vupen.com/english/advisories/2005/2292