Summary

This security update resolves a Microsoft Excel remote code execution vulnerability. To learn more about the vulnerability, see Microsoft Common Vulnerabilities and Exposures CVE-2021-38655.

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.

More information

Security update deployment information

For deployment information about this update, see Security update deployment information: September 14, 2021 (KB5005848).

Security update replacement information

This security update replaces previously released security update 5001973.

File hash information

File name

SHA256 hash

wacserver2019-kb5001999-fullfile-x64-glb.exe

416C5C259A0CFF67D4BD4681F8EF42BB24C8C0A846D5D1B4B4E1274C3DD3B9AE

File information

Download the list of files that are included in security update 5001999.

Information about protection and security

Protect yourself online: Windows Security support

Learn how we guard against cyber threats: Microsoft Security

Need more help?

Expand your skills
Explore Training
Get new features first
Join Microsoft Insiders

Was this information helpful?

What affected your experience?

Any additional feedback? (Optional)

Thank you for your feedback!

×