Resolves a weakness in the CPU chipset microcode that could allow instructions from a Hyper-V guest to put its Hyper-V host's CPU in an unresponsive state. This could lead to a denial of service condition for the guest operating systems that are running on the affected host.

Resolves a vulnerability in Windows that could allow elevation of privilege if an attacker passes a specially crafted function in a hypercall from one running virtual machine to another running virtual machine on the same host.

We've added this issue to our memory dump diagnostic which can confirm. On a computer that is running Windows Server 2008 Service Pack 2 (SP2) or Windows Server 2008 R2 together with the Hyper-V role installed, you receive an error message that resembles the following:

For all supported x64-based versions. Resolves a vulnerability in Windows that could allow remote code execution if an authenticated attacker on a guest operating system runs a specially crafted application that causes the Hyper-V host operating system to execute arbitrary code.

Apply this hotfix only to systems that are experiencing the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

Resolves a vulnerability in Windows that could allow remote code execution.

To apply this hotfix, your computer must be running Windows Server 2008 R2. Additionally, you must have Hyper-V role installed on your computer. You have to restart the computer after you apply this hotfix. To use one of the hotfixes in this package, you do not have to make any changes to the registry.

To start a Windows Server 2008 x86-based virtual machine on a computer that uses a 6-core processor, you also have to install hotfix 950182.

To apply this hotfix, you must be running Windows Server 2008 R2 and have the Hyper-V role installed. You must restart the computer after you apply this hotfix. This hotfix does not replace a previously released hotfix.

Fixes an issue in which the network connection of a running Hyper-V virtual machine may be lost under heavy outgoing network traffic. This issue occurs on a computer that is running Windows Server 2008 R2 SP1.