An elevation of privilege vulnerability exists when Windows Hyper-V instruction emulation fails to properly enforce privilege levels. An attacker who successfully exploited this vulnerability could gain elevated privileges on a target guest operating system. The host operating system is not vulnerable to this attack.
This vulnerability by itself does not allow arbitrary code to be run. However, the vulnerability could be used in conjunction with one or more vulnerabilities (e.g. a remote code execution vulnerability and another elevation of privilege) that could take advantage of the elevated privileges when running.
The update addresses the vulnerability by correcting how privileges are enforced by Windows Hyper-V instruction emulation.