Hyper-V in Microsoft Windows Server 2008 Gold, SP2, and R2 allows guest OS users to cause a denial of service (host OS hang) by sending a crafted encapsulated packet over the VMBus, aka "Hyper-V VMBus Vulnerability."
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.