Unspecified vulnerability in the VMware Descheduled Time Accounting driver in VMware Workstation 6.5.1 and earlier, VMware Player 2.5.1 and earlier, VMware ACE 2.5.1 and earlier, VMware Server 1.x before 1.0.9 build 156507 and 2.x before 2.0.1 build 156745, VMware Fusion 2.x before 2.0.2 build 147997, VMware ESXi 3.5, and VMware ESX 3.0.2, 3.0.3, and 3.5, when the Descheduled Time Accounting Service is not running, allows guest OS users on Windows to cause a denial of service via unknown vectors.