Unspecified vulnerability in Microsoft IIS 6.0, 7.0, and 7.5, when Extended Protection for Authentication is enabled, allows remote authenticated users to execute arbitrary code via unknown vectors related to "token checking" that trigger memory corruption, aka "IIS Authentication Memory Corruption Vulnerability." Per: http://www.microsoft.com/technet/security/bulletin/ms10-040.mspx
'Mitigating Factors for IIS Authentication Memory Corruption Vulnerability - CVE-2010-1256
Without the installation of KB973917 on Windows Server 2003, Windows Vista, and Windows Server 2008, systems will not have the Extended Protection for Authentication feature and will not be vulnerable.
Extended Protection for Authentication is not enabled by default on any affected platform, even when a system has installed KB973917. Systems are only affected when this feature is enabled.'