The Outlook Express Address Book control, when using Internet Explorer 6, allows remote attackers to cause a denial of service (NULL dereference and browser crash) by creating the OutlookExpress.AddressBook COM object, which is not intended for use within Internet Explorer.
https://exchange.xforce.ibmcloud.com/vulnerabilities/34755
http://www.securityfocus.com/archive/1/470694/100/0/threaded
http://www.securityfocus.com/archive/1/391803
http://browserfun.blogspot.com/2006/07/mobb-3-outlookexpressaddressbook_02.html