Microsoft Security Bulletin MS13-049 - connspiracy theory

Executive Summary

This security update resolves a privately reported vulnerability in Microsoft Windows. The vulnerability could allow denial of service if an attacker sends specially crafted packets to the server. Firewall best practices and standard default firewall configurations can help protect networks from attacks that originate outside the enterprise perimeter.
This security update is rated Important for all supported editions of Windows 8, Windows Server 2012, and Windows RT, and Moderate for all supported editions of Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2. For more information, see the subsection, Affected and Non-Affected Software, in this section.
The security update addresses the vulnerability by correcting the way that the Windows TCP/IP driver handles specially crafted packets. For more information about the vulnerability, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.

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there is rumor that such kind of vulnerability is on purpose, which was an secret backdoor created for "big brother" surveillance.

This was release in co-incidence with Edward Snowden's disclosure.

Is this an on-purpose exploit used by NSA?