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Microsoft Security Bulletin MS06-049 - Important

Vulnerability in Windows Kernel Could Result in Elevation of Privilege (920958)

Published: | Updated:

Version: 2.0


Who Should Read this Document: Customers who use Microsoft Windows

Impact of Vulnerability: Elevation of Privilege

Maximum Severity Rating: Important

Recommendation: Customers should apply the update at the earliest opportunity

Security Update Replacement: This bulletin replaces a prior security update. See the frequently asked questions (FAQ) section of this bulletin for the complete list.

Caveats: Microsoft Knowledge Base Article 920958 documents the currently known issues that customers may experience when they install this security update. The article also documents recommended solutions for these issues. For more information, see Microsoft Knowledge Base Article 920958.

Tested Software and Security Update Download Locations:

Affected Software:

Non-Affected Software:

  • Microsoft Windows XP Service Pack 1 and Microsoft Windows XP Service Pack 2
  • Microsoft Windows XP Professional x64 Edition
  • Microsoft Windows Server 2003 and Microsoft Windows Server 2003 Service Pack 1
  • Microsoft Windows Server 2003 for Itanium-based Systems and Microsoft Windows Server 2003 with SP1 for Itanium-based Systems
  • Microsoft Windows Server 2003 x64 Edition

The software in this list has been tested to determine whether the versions are affected. Other versions either no longer include security update support or may not be affected. To determine the support life cycle for your product and version, visit the Microsoft Support Lifecycle Web site.

General Information

Executive Summary

Frequently Asked Questions (FAQ) Related to This Security Update

Vulnerability Details

Security Update Information

Other Information

Obtaining Other Security Updates:

Updates for other security issues are available at the following locations:


  • Customers in the U.S. and Canada can receive technical support from Microsoft Product Support Services at 1-866-PCSAFETY. There is no charge for support calls that are associated with security updates.
  • International customers can receive support from their local Microsoft subsidiaries. There is no charge for support that is associated with security updates. For more information about how to contact Microsoft for support issues, visit the International Support Web site.

Security Resources:

Software Update Services:

By using Microsoft Software Update Services (SUS), administrators can quickly and reliably deploy the latest critical updates and security updates to Windows 2000 and Windows Server 2003-based servers, and to desktop systems that are running Windows 2000 Professional or Windows XP Professional.

For more information about how to deploy security updates by using Software Update Services, visit the Software Update Services Web site.

Windows Server Update Services:

By using Windows Server Update Services (WSUS), administrators can quickly and reliably deploy the latest critical updates and security updates for Windows 2000 operating systems and later, Office XP and later, Exchange Server 2003, and SQL Server 2000 onto Windows 2000 and later operating systems.

For more information about how to deploy security updates using Windows Server Update Services, visit the Windows Server Update Services Web site.

Systems Management Server:

Microsoft Systems Management Server (SMS) delivers a highly configurable enterprise solution for managing updates. By using SMS, administrators can identify Windows-based systems that require security updates and can perform controlled deployment of these updates throughout the enterprise with minimal disruption to end users. For more information about how administrators can use SMS 2003 to deploy security updates, visit the SMS 2003 Security Patch Management Web site. SMS 2.0 users can also use Software Updates Service Feature Pack to help deploy security updates. For information about SMS, visit the SMS Web site.

Note SMS uses the Microsoft Baseline Security Analyzer, the Microsoft Office Detection Tool, and the Enterprise Update Scan Tool to provide broad support for security bulletin update detection and deployment. Some software updates may not be detected by these tools. Administrators can use the inventory capabilities of the SMS in these cases to target updates to specific systems. For more information about this procedure, visit the following Web site. Some security updates require administrative rights following a restart of the system. Administrators can use the Elevated Rights Deployment Tool (available in the SMS 2003 Administration Feature Pack and in the SMS 2.0 Administration Feature Pack) to install these updates.


The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.


  • V1.0 (August 08, 2006): Bulletin published.
  • V1.1 (September 13, 2006): Caveats section updated to reflect known issues with installation of security update.
  • V2.0 (September 26, 2006): The update has been revised and re-released for Microsoft Windows 2000 Service Pack 4 to address issues identified in Microsoft Knowledge Base Article 920958.