Microsoft Internet Explorer 10 and 11 allows remote attackers to gain privileges via a crafted web site, as demonstrated by a transition from Low Integrity to Medium Integrity, aka "Internet Explorer Elevation of Privilege Vulnerability."
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-106
http://www.zerodayinitiative.com/advisories/ZDI-15-545