This indicates an attack attempt to exploit a Memory Corruption vulnerability in Microsoft Internet Explorer.
The vulnerability is due to an error when the vulnerable software attempts to access an object that has been deleted. An attacker can exploit this by tricking a user into visiting a malicious webpage and execute arbitrary code within the context of the application.
Internet Explorer 8
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.