Microsoft Internet Explorer 8 through 11 and Microsoft Edge mishandle HTML attributes in HTTP responses, which allows remote attackers to bypass a cross-site scripting (XSS) protection mechanism via unspecified vectors, aka "Microsoft Browser XSS Filter Bypass 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