Cross-site scripting (XSS) vulnerability in u2u.php in XMB Forums 1.9.3 and earlier allows remote attackers to inject arbitrary web script or HTML via the username parameter, as demonstrated using a URL-encoded iframe tag.
https://exchange.xforce.ibmcloud.com/vulnerabilities/24647
https://docs.xmbforum2.com/index.php?title=Security_Issue_History
http://www.vupen.com/english/advisories/2006/0529
http://www.securityfocus.com/bid/16604
http://www.securityfocus.com/archive/1/425084/100/0/threaded