The ICQPhone.SipxPhoneManager ActiveX control in America Online ICQ 5.1 allows remote attackers to download and execute arbitrary code via the DownloadAgent function, as demonstrated using an ICQ avatar.
https://exchange.xforce.ibmcloud.com/vulnerabilities/30059
http://www.zerodayinitiative.com/advisories/ZDI-06-037.html
http://www.vupen.com/english/advisories/2006/4362
http://www.securityfocus.com/bid/20930
http://www.securityfocus.com/archive/1/450726/100/0/threaded
http://securitytracker.com/id?1017163