Microsoft Security Advisory (2718704): Unauthorized Digital Certificates Could Allow Spoofing - Version: 1.0

Revision Note: V1.0 (June 3, 2012): Advisory published.
Summary: Microsoft is aware of active attacks using three unauthorized digital certificates derived by a Microsoft Certificate Authority. An unauthorized certificate could be used to spoof content, perform phishing attacks, or perform man-in-the-middle attacks against all Web browser users including users of Internet Explorer. This issue affects all supported releases of Microsoft Windows.

More...

This has been posted as an out-of-band update (KB2718704) on Windows Update. A compromised certificate authority server is a serious problem. This update has even been posted to the Windows 8 Consumer Preview. Please check Windows Update today and update your systems.

A great public service post . A must get update . Your computer is very vulnerable without this update .