Microsoft has issued a formal security advisory to confirm the remote reboot flaw in its implementation of the SMB2 protocol. A successful attack could lead to remote code execution and full system takeover. The vulnerability, which was originally released as a denial-of-service issue, does not affect the RTM version of Windows 7. It appears Microsoft fixed the flaw in Windows 7 build ~7130, just after RC1. Windows Vista and Windows Server 2003 users remain at risk. In the absence of patch, Microsoft recommends users disable SMB v2 and block TCP ports 139 and 445 at the firewall.
Source: https://threatpost.com/microsoft-confirms-smb2-flaw-heightens-severity-091109/72229/