Unspecified vulnerability in a guest virtual device driver in VMware Workstation before 5.5.9 build 126128, and 6.5.1 and earlier 6.x versions; VMware Player before 1.0.9 build 126128, and 2.5.1 and earlier 2.x versions; VMware ACE before 1.0.8 build 125922, and 2.5.1 and earlier 2.x versions; VMware Server 1.x before 1.0.8 build 126538 and 2.0.x before 2.0.1 build 156745; VMware Fusion before 2.0.1; VMware ESXi 3.5; and VMware ESX 3.0.2, 3.0.3, and 3.5 allows guest OS users to cause a denial of service (host OS crash) via unknown vectors.