This indicates an attack attempt to exploit a Privilege Escalation vulnerability in Microsoft Windows.
The vulnerability is caused by an integer overflow issue in win32k.sys. An attacker can exploit this to elevate their privileges on vulnerable systems.
Windows Server 2008
Windows Server 2012 and Windows Server 2012 R2
Windows RT 8.1
Privilege Escalation: Remote attackers can leverage their privilege on the vulnerable systems.
Apply the most recent upgrade or patch from the vendor