This indicates an attack attempt to exploit an Information Disclosure 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 obtain sensitive information.
Internet Explorer 10
Internet Explorer 11
Information Disclosure: Remote attackers can gain sensitive information from vulnerable systems.
Apply the most recent upgrade or patch from the vendor.