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This security update resolves several reported vulnerabilities in Internet Explorer. The most severe of these vulnerabilities could allow remote code execution if a user views a specially crafted webpage in Internet Explorer. To learn more about these vulnerabilities, see Microsoft Common Vulnerabilities and Exposures.  

Additionally, see the following articles for more information about this cumulative update:


  • The fixes that are included in this Security Update for Internet Explorer 4040685 are also included in the October 2017 Security Monthly Quality Rollup. Installing either the Security Update for Internet Explorer or the Security Monthly Quality Rollup installs the fixes that are resolved in this update.

  • If you use update management processes other than Windows Update and you automatically approve all security updates classifications for deployment, this Security Update for Internet Explorer 4040685, the October 2017 Security Only Quality Update, and the October 2017 Security Monthly Quality Rollup are deployed. We recommend that you review your update deployment rules to make sure that the desired updates are deployed.

  • This Security Update for Internet Explorer is not applicable for installation on a computer where the Security Monthly Quality Rollup or the Preview of Monthly Quality Rollup from October 2017 (or a later month) is already installed. This is because those updates contain all fixes that are in this Security Update for Internet Explorer.

If you install a language pack after you install this update, you must reinstall this update. Therefore, we recommend that you install any language packs that you need before you install this update. For more information, see Add language packs to Windows.

Deployment information

For deployment details for this security update, see the following article in the Microsoft Knowledge Base:

Security update deployment information: October 10, 2017

Known issues in this update



After installing KB4040685, Internet Explorer 11 package users may receive an error message that states that an application exception has occurred when some applications are closed. This can affect applications that use mshtml.dll to load web content. This problem occurs only when a process is already shutting down. It does not affect application functionality.

This issue is resolved in security update 4047206.

After installing this KB, Internet Explorer 11 users who use SQL Server Reporting Services (SSRS) may not be able to scroll through a drop-down menu by using the scroll bar.

Using the scroll wheel on a mouse works as expected. Additionally, this issue is applicable to only document mode 11. Therefore, trying to load the page by using document mode 10 may work around the issue.

To change the document mode in Internet Explorer 11:

  1. Select F12.

  2. Select the Emulation tab.

  3. In the Document mode menu, select 10. The page reloads in the new document mode.

Note F12 tools are available on any page that you are viewing in Internet Explorer. To access the tools, select F12. Or, select the tools button Tools, and then select F12 Developer Tools.

Microsoft is working on a resolution and will provide an update in an upcoming release.

How to get and install the update

Method 1: Microsoft Update

This update is available through Microsoft Update. When you turn on automatic updating, this update will be downloaded and installed automatically.

For more information about how to get security updates automatically, see Windows Update: FAQ.

Note For Windows RT and Windows RT 8.1, this update is available through Microsoft Update only.

Method 2: Microsoft Update Catalog

To get the stand-alone package for this update, go to the Microsoft Update Catalog website.

More Information

Help for installing updates: Windows Update: FAQ

Security solutions for IT professionals: TechNet Security Support and Troubleshooting

Help for protecting your Windows-based computer from viruses and malware: Microsoft Secure

Local support according to your country: International Support

File information

For a list of the files that are provided in this cumulative update, download the file information for cumulative update 4040685.

File hash information

File name

SHA1 hash

SHA256 hash






















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