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Microsoft Security Bulletin MS13-051 - Important

Vulnerability in Microsoft Office Could Allow Remote Code Execution (2839571)


Version: 1.0

General Information

Executive Summary

This security update resolves one privately reported vulnerability in Microsoft Office. The vulnerability could allow remote code execution if a user opens a specially crafted Office document using an affected version of Microsoft Office software, or previews or opens a specially crafted email message in Outlook while using Microsoft Word as the email reader. An attacker who successfully exploited this vulnerability could gain the same user rights as the current user. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

This security update is rated Important for supported editions of Microsoft Office 2003 and Microsoft Office for Mac 2011. 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 Microsoft Office parses specially crafted Office files. For more information about the vulnerability, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.

Recommendation. Customers can configure automatic updating to check online for updates from Microsoft Update by using the Microsoft Update service. Customers who have automatic updating enabled and configured to check online for updates from Microsoft Update typically will not need to take any action because this security update will be downloaded and installed automatically. Customers who have not enabled automatic updating need to check for updates from Microsoft Update and install this update manually. For information about specific configuration options in automatic updating, see Microsoft Knowledge Base Article 294871.

For administrators and enterprise installations, or end users who want to install this security update manually, Microsoft recommends that customers apply the update at the earliest opportunity using update management software, or by checking for updates using the Microsoft Update service.

For customers of Microsoft Office for Mac, Microsoft AutoUpdate for Mac can be configured to deliver updates for Microsoft software directly to your system. For more information, see Check for Office for Mac updates automatically.

See also the section, Detection and Deployment Tools and Guidance, later in this bulletin.

Knowledge Base Article

Knowledge Base Article2839571
File informationYes
SHA1/SHA2 hashesYes
Known issuesYes

Affected and Non-Affected Software

The following software has been tested to determine which versions or editions are affected. Other versions or editions are either past their support life cycle or are not affected. To determine the support life cycle for your software version or edition, see Microsoft Support Lifecycle.

Affected Software

Microsoft Office Suite and Other SoftwareMaximum Security ImpactAggregate Severity RatingUpdates Replaced
Microsoft Office 2003 Service Pack 3
Remote Code ExecutionImportant2584052 in MS11-073
Microsoft Office for Mac 2011
Remote Code ExecutionImportant2817452 in MS13-026


Non-Affected Software 

Office and Other Software
Microsoft Office 2007 Service Pack 3
Microsoft Office 2010 Service Pack 1
Microsoft Office 2013
Microsoft Office 2013 RT
Microsoft Office Compatibility Pack Service Pack 3
Microsoft Excel Viewer
Microsoft PowerPoint Viewer

Update FAQ

Vulnerability Information

Severity Ratings and Vulnerability Identifiers

Office Buffer Overflow Vulnerability - CVE-2013-1331

Update Information

Detection and Deployment Tools and Guidance

Security Update Deployment

Other Information


Microsoft thanks the following for working with us to help protect customers:

  • Andrew Lyons and Neel Mehta of Google Inc for reporting the Office Buffer Overflow Vulnerability (CVE-2013-1331)

Microsoft Active Protections Program (MAPP)

To improve security protections for customers, Microsoft provides vulnerability information to major security software providers in advance of each monthly security update release. Security software providers can then use this vulnerability information to provide updated protections to customers via their security software or devices, such as antivirus, network-based intrusion detection systems, or host-based intrusion prevention systems. To determine whether active protections are available from security software providers, please go to the active protections websites provided by program partners, listed in Microsoft Active Protections Program (MAPP) Partners.


How to obtain help and support for this security update


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 (June 11, 2013): Bulletin published.