Recently Microsoft was in the news for its training materials for Best Buy employees, which falsely claims Windows' "superiority" over Linux. Not even a week has passed since that incident than a serious security flaw affecting Windows Vista and the yet-to-be-released Windows 7 has been reported.
The vulnerability has been reported to due to the way Windows Vista and Windows 7 handles SMB2 protocol. It has been reported that this vulnerability can result in an attacker being able to remotely crash the machine running Windows Vista and Windows 7 with SMB(Server Message Block) enabled. There are also suggestions that this vulnerability can be used to execute denial of service and remote code execution, both of which are potentially very damaging to the affected system.
Microsoft has not yet released any patch for this vulnerabilty. So, currently, the only security measure seems to be closing the SMB port.
Maybe next time Microsoft should concentrate on fixing its Operating System before trying to discredit other (read Linux) with its "claimed" superiority.