Microsoft decided to release the update, Microsoft Security Bulletin MS06-055, now and ahead of its normal monthly scheduled round of security updates.

From Microsoft statement...

"Microsoft originally planned to release the update on Tuesday, October 10, 2006 as part of its regular monthly release of security bulletins. However, Microsoft is aware of the existence of a public attack utilizing the vulnerability. Since testing has been completed earlier than anticipated, Microsoft has released the update ahead of schedule to help protect customers. "

Software affected...

Windows XP Tablet PC Edition

Windows XP Home Edition

Windows XP Media Center Edition

Windows XP Professional

Windows XP Professional 64-Bit Edition

Windows Server 2003 Web Edition

Windows Server 2003 Standard Edition

Windows Server 2003 Enterprise Edition

Windows Server 2003 Datacenter Edition

Windows Server 2003 for Small Business Server

Windows Server 2003 Enterprise Edition for Itanium-based Systems

Windows Server 2003 Datacenter Edition for Itanium-based Systems

Windows 2000 Server

Windows 2000 Professional

Windows 2000 Datacenter Server

Windows 2000 Advanced Server

Internet Explorer 5.01

Internet Explorer 6.0

Windows Server 2003 Datacenter x64 Edition

Windows Server 2003 Enterprise x64 Edition

Windows Server 2003 Standard x64 Edition

Updates are available from the Microsoft web site Windows Update area.