This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Microsoft Internet Explorer. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.
The specific flaw exists within the way Internet Explorer handles CCaret objects. After the CCaret object has been freed there exists a race condition to reclaim the target objects heap buffer before a background thread issues a message to update the screen caret and reuse the stale pointer. An attacker can leverage this vulnerability to execute code under the context of the current process.