Who should read this bulletin: All customers using the Microsoft® MSN Chat control, which is available for direct download and ships with MSN Messenger and Exchange Instant Messenger.

Impact of vulnerability: Run Code of Attacker's Choice

Maximum Severity Rating: Critical

Affected Software:

Microsoft MSN Chat Control
Microsoft MSN Messenger 4.5 and 4.6, which includes the MSN Chat control
Microsoft Exchange Instant Messenger 4.5 and 4.6, which includes the MSN Chat control

Download the patch here