VMware Workstation 8.x before 8.0.3, VMware Player 4.x before 4.0.3, VMware Fusion 4.x before 4.1.2, VMware ESXi 3.5 through 5.0, and VMware ESX 3.5 through 4.1 do not properly register SCSI devices, which allows guest OS users to cause a denial of service (invalid write operation and VMX process crash) or possibly execute arbitrary code on the host OS by leveraging administrative privileges on the guest OS.