Microsoft SharePoint Server 2013 Gold and SP1 and SharePoint Foundation 2013 Gold and SP1 allow remote authenticated users to gain privileges via a Trojan horse app that executes a custom action in the context of the SharePoint extensibility model, aka "SharePoint Page Content Vulnerability."
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2014/ms14-050
http://www.securitytracker.com/id/1030720