Microsoft Internet Explorer 11 and Microsoft Edge mishandle content types, which allows remote attackers to execute arbitrary web script in a privileged context via a crafted web site, aka "Microsoft Browser Elevation of Privilege Vulnerability."
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-125
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-124