This indicates an attack attempt to exploit a Cross-Site Scripting vulnerability in Microsoft Internet Explorer.
The vulnerability is due to an error when the vulnerable software handles a maliciously crafted html file. An attacker can exploit this by tricking an unsuspecting user into visiting a malicious webpage and execute arbitrary script code within the context of the application.
Internet Explorer 9
Internet Explorer 10
Internet Explorer 11
Internet Explorer 11 on Windows 10
System Compromise: Remote attackers can execute arbitrary script code within the context of the target user's browser.
Apply the most recent upgrade or patch from the vendor.