An important security update, described in MS11-051 (http://go.microsoft.com/fwlink/?LinkId=217101) was released today. The update fixes a cross-site scripting vulnerability in the sample web enrollment ASP pages that are part of Active Directory Certificate Services Web Enrollment in Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.
Important: Back up any sample web enrollment sample pages you modified (%windir%\system32\Certsrv) before applying MS11-051. After you apply the security update, you can integrate any changes you made to the original sample files into the new secure ASP sample pages. For more information, see Microsoft Knowledge Base Article 2518295 (http://support.microsoft.com/kb/2518295).