Technical Information

Brief overview of the risk:
This security update resolves two privately reported vulnerabilities in the Microsoft Distributed File System (DFS). The more severe of these vulnerabilities could allow remote code execution when an attacker sends a specially crafted DFS response to a client-initiated DFS request.
Detailed Information on the risk:

An unauthenticated remote code execution vulnerability exists in the way that the Distributed File System (DFS) client parses specially crafted DFS responses. An attempt to exploit the vulnerability would not require authentication, allowing an attacker to exploit the vulnerability by sending a specially crafted DFS response to a client-initiated DFS request. An attacker who successfully exploited this vulnerability could execute arbitrary code and take complete control of an affected system.

Further information on this exploit is available at : MS11-042