Severity Rating: Important
Revision Note: V1.0 (June 14, 2011): Bulletin published.
Summary: This security update resolves a privately reported vulnerability in Windows Server 2008 Hyper-V and Windows Server 2008 R2 Hyper-V. The vulnerability could allow denial of service if a specially crafted packet is sent to the VMBus by an authenticated user in one of the guest virtual machines hosted by the Hyper-V server. An attacker must have valid logon credentials and be able to send specially crafted content from a guest virtual machine to exploit this vulnerability. The vulnerability could not be exploited remotely or by anonymous users.