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This security update resolves a Microsoft Word remote code execution vulnerability. To learn more about the vulnerability, see Microsoft Common Vulnerabilities and Exposures CVE-2021-28453.

Note: To apply this security update, you must have the release version of Microsoft SharePoint Server 2019 installed on the computer.

Improvements and fixes

This update contains fixes for the following nonsecurity issues:

  • Fixes an issue in which the focus border is cropped on the "News" link in the "News" web part.

  • Fixes an issue on the Search Result page in which the Search filter isn't defined by having a complementary landmark.

  • Fixes an issue in which the focus moves to the non-interactive elements in a News Card on the Start page.

  • Fixes an issue on the Document page in which the focus moves to the New button when the View Options menu is closed.

  • Fixes an issue in the screen reader while it's in scan mode in which it reads out some hidden contents after the Cancel button is selected in the Create Communication Site pane.

Note: To fix these issues, you have to install KB 4504716 together with this update.

Known issue in this update


After you install this update, you can no longer delete list item attachments in the item detail panel.


Microsoft is investigating this issue and will post more information in this article when a fix becomes available.


To work around this issue, see KB 5003294.

How to get and install the update

Method 1: Microsoft Update

This update is available from 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.

Method 2: Microsoft Update Catalog

To get the standalone package for this update, go to the Microsoft Update Catalog website.

Method 3: Microsoft Download Center

You can get the standalone update package through the Microsoft Download Center. Follow the installation instructions on the download page to install the update.

More information

Security update deployment information

For deployment information about this update, see Security update deployment information: April 13, 2021.

Security update replacement information

This security update replaces previously released security update 4493231.

File hash information

File name

SHA1 hash

SHA256 hash




File information

Download the list of files that are included in security update 4504715.

Information about protection and security

Protect yourself online: Windows Security support

Learn how we guard against cyber threats: Microsoft Security

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