Design/Logic Flaw

Use-after-free vulnerability in the kernel-mode drivers in Microsoft Windows Vista SP1 and SP2 and Server 2008 Gold and SP2 allows local users to gain privileges or cause a denial of service (system crash) by using a large number of calls to the NtUserCheckAccessForIntegrityLevel function to trigger a failure in the LockProcessByClientId function, leading to deletion of an in-use process object, aka “Win32k Reference Count Vulnerability.”