Microsoft Security Bulletin MS11-100 - Critical

Microsoft released an out-of-band patch today for .NET

Vulnerabilities in .NET Framework Could Allow Elevation of Privilege (2638420)

Recommendation. The majority of customers have automatic updating enabled and will not need to take any action because this security update will be downloaded and installed automatically. Customers who have not enabled automatic updating need to check for updates and install this update manually.

Thanks. I got the notification from Windows Update and installed it.