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This security update resolves a Microsoft SharePoint Server remote code execution vulnerability. To learn more about the vulnerability, see Microsoft Common Vulnerabilities and Exposures CVE-2021-31966.

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 security update contains fixes for the following nonsecurity issues:

  • Fixes an issue where metadata about the Public Update that was stored in the Windows Registry contained non-printable characters.

  • Removes the engagement log query parameter "e" from copy links for On-Premises because it's only used in SharePoint Online.

  • Fixes the issue in which the screen reader doesn't read the text of the Quick links web part title that's given by a user.

  • Fixes the issue in which the screen reader doesn't read letters when you delete words.

  • Fixes the issue where the posted news doesn't show up in the "News" web part in Internet Explorer by using the list layout.

  • Fixes the role relationship issue at the "Document" page for accessibility.

  • Fixes the issue in which the ARIA toggle field in details list doesn't have an accessible name.

  • Fixes the issue where the New Items under Site Usage in a non-English modern team site only counts .docx files.

Note: To fix these issues, you have to install KB 5001944 together with this update.

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: June 8, 2021 (KB5004128).

Security update replacement information

This security update replaces previously released security update 4504715.

File hash information

File name

SHA256 hash



File information

Download the list of files that are included in security update 5001945.

Information about protection and security

Protect yourself online: Windows Security support

Learn how we guard against cyber threats: Microsoft Security

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