This security update is being released out of band in conjunction with Microsoft Security Bulletin MS09-035, which describes vulnerabilities in those components and controls that have been developed using vulnerable versions of the Microsoft Active Template Library (ATL). As a defense-in-depth measure, this Internet Explorer security update helps mitigate known attack vectors within Internet Explorer for those components and controls that have been developed with vulnerable versions of ATL as described in Microsoft Security Advisory (973882) and Microsoft Security Bulletin MS09-035.

This security update also resolves three privately reported vulnerabilities in Internet Explorer. These vulnerabilities could allow remote code execution if a user views a specially crafted Web page using Internet Explorer. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

This security update is rated Critical for Internet Explorer 5.01 and Internet Explorer 6 Service Pack 1, running on supported editions of Microsoft Windows 2000; Critical for Internet Explorer 6, Internet Explorer 7, and Internet Explorer 8 running on supported editions of Windows XP; Critical for Internet Explorer 7 and Internet Explorer 8 running on supported editions of Windows Vista; Moderate for Internet Explorer 6, Internet Explorer 7, and Internet Explorer 8 running on supported editions of Windows Server 2003; and Moderate for Internet Explorer 7 and Internet Explorer 8 running on supported editions of Windows Server 2008. For more information, see the subsection, Affected and Non-Affected Software, in this section.