Microsoft » Windows Server 2012 : Security Vulnerabilities, CVEs, Published In July 2015 (Denial of service)

Hyper-V in Microsoft Windows 8.1 and Windows Server 2012 R2 does not properly initialize guest OS system data structures, which allows guest OS users to execute arbitrary code on the host OS or cause a denial of service (buffer overflow) by leveraging guest OS privileges, aka "Hyper-V Buffer Overflow Vulnerability."