With the release of Security Advisory 2028859, Microsoft Security Response Center warned users of Windows 7 x64, Windows Server 2008 R2 x64, and Windows Server 2008 R2 for Itanium systems about a vulnerability in the Canonical Display which if exploited, could cause the affected system to be unresponsive and show problems in restart.
There is a possibility of code execution, but could have difficulties because of memory randomization. But, to be on the safer side MSRC recommends users of above mentioned Windows versions to disable Aero theme as this vulnerability only affects systems with installed and enabled Aero theme. With Aero disabled, the path by which Canonical Display driver can be affected is bypassed.
More information is at the official MSRC blog at http://blogs.technet.com/msrc/archive/2010/05/18/security-advisory-2028859-released.aspx
Security Advisory 2028859 http://www.microsoft.com/technet/security/advisory/2028859.mspx