Revision Note: V5.0 (September 19, 2011): Revised to announce the rerelease of the KB2616676 update. See the Update FAQ in this advisory for more information.
Summary: Microsoft is aware of active attacks using at least one fraudulent digital certificate issued by DigiNotar, a certification authority present in the Trusted Root Certification Authorities Store. A fraudulent 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. While this is not a vulnerability in a Microsoft product, this issue affects all supported releases of Microsoft Windows.