Cross-site scripting (XSS) vulnerability in Invision Power Board 2.3.1 and earlier allows remote attackers to inject arbitrary web script or HTML via an IFRAME tag in the signature.
https://exchange.xforce.ibmcloud.com/vulnerabilities/41502
http://www.securityfocus.com/bid/28466
http://www.securityfocus.com/archive/1/490115/100/0/threaded