Win32k flaw is an elevation of privilege vulnerability, which exists in Windows when the Win32k component fails to properly handle objects in memory. Win32k is the Windows kernel driver.
Specifically, the flaw is a race condition that is present in the win32k driver due to a lack of proper synchronization between undocumented system calls (NtDCompositionDiscardFrame and NtDCompositionDestroyConnection). A race condition occurs when system attempts to perform two or more operations at the same time.
To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and take control of an affected system.
Microsoft Windows 8 to 10 build 15063 64-bit operating systems
Microsoft has patched this vulnerability.