Microsoft Internet Explorer 11 allows remote attackers to gain privileges via a crafted web site, as demonstrated by a transition from Low Integrity to Medium Integrity, aka "Elevation of Privilege Vulnerability."
https://euvd.enisa.europa.eu/vulnerability/EUVD-2015-2582
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-094