Multiple use-after-free vulnerabilities in Microsoft Internet Explorer 6 through 11 allow remote attackers to execute arbitrary code via unspecified vectors, as demonstrated by Sebastian Apelt and Andreas Schmidt during a Pwn2Own competition at CanSecWest 2014.
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2014/ms14-037
http://www.securitytracker.com/id/1030532