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 (KB 4457426) are also included in the September 2018 Security Monthly Quality Rollup. Installing either the Security Update for Internet Explorer or the Security Monthly Quality Rollup installs the fixes that are 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 (KB 4457426), the September 2018 Security Only Quality Update, and the September 2018 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 on which the Security Monthly Quality Rollup or the Preview of Monthly Quality Rollup from September 2018 (or a later month) is already installed. This is because those updates contain all the 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.
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.