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This security update resolves Microsoft SharePoint information disclosure vulnerability and SharePoint spoofing vulnerability. To learn more about these vulnerabilities, see Microsoft Common Vulnerabilities and Exposures CVE-2020-17115 and Microsoft Common Vulnerabilities and Exposures CVE-2020-17120.

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. To fixes these issues completely, you have to install KB 4486751 together with this update.

  • Avoids unnecessary SP.Directory.DirectorySession server calls on pages.

  • Fixes an issue in which a modern document library shows duplicate files and the duplicate files vanish after a refresh.

  • Fixes an issue in which the "site permission" icon doesn't work on the OneDrive.aspx page.

  • Fixes an issue in which the Change the look button on the RecycleBin.aspx page doesn't work.

  • Fixes an issue in which the Compact list view mode is invalid on the RecycleBin.aspx page.

  • Fixes an issue in which document library item information and the activity pane keep reloading if the document library is grouped.

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: December 8, 2020.

Security update replacement information

This security update replaces previously released security update 4484504.

File hash information

File name

SHA1 hash

SHA256 hash




File information

Download the list of files that are included in security update 4486752.

Information about protection and security

Protect yourself online: Windows Security support

Learn how we guard against cyber threats: Microsoft Security

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