This vulnerability allows remote attackers to escalate privileges 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 handling of registry links. An attacker running code in a low-integrity Internet Explorer process can set a registry link that will be followed by the medium-integrity broker process, which will then reduce the security of the target registry key in such a way that it can be modified by low-integrity Internet Explorer processes. These registry keys can be used to execute medium-integrity processes from low-integrity Internet Explorer processes.