This security update resolves Microsoft Word remote code execution vulnerability, Microsoft Excel remote code execution vulnerability, and Microsoft Excel information disclosure vulnerability. To learn more, see the following security advisories:
Note: To apply this security update, you must have the release version of Microsoft Office Online Server installed on the computer.
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.
Security update deployment information
For deployment information about this update, see Security update deployment information: April 13, 2021 (KB5001866).
Security update replacement information
This security update replaces previously released security update 4493229.
File hash information
Information about protection and security
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