Array index error in win32k.sys in the kernel-mode drivers in Microsoft Windows 8, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 allows local users to cause a denial of service (reboot) via a crafted TrueType font (TTF) file, aka "TrueType Font Parsing Vulnerability."
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2013/ms13-101