The ShellExecute API in Windows Shell in Microsoft Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 does not properly implement file associations, which allows local users to gain privileges via a crafted application, as exploited in the wild in May 2014, aka "Windows Shell File Association Vulnerability."
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2014/ms14-027