The Microsoft Office Outlook Recipient ActiveX control (ole32.dll) in Windows XP SP2 allows remote attackers to cause a denial of service (Internet Explorer 7 hang) via crafted HTML.
Microsoft email clients in Outlook, Exchange, and Windows Messaging automatically respond to Read Receipt and Delivery Receipt tags, which could allow an attacker to flood a mail system with responses by forging a Read Receipt request that is redirected to a large distribution list.
The Microsoft Active Setup ActiveX component in Internet Explorer 4.x and 5.x allows a remote attacker to install software components without prompting the user by stating that the software's manufacturer is Microsoft.