KB5002821: This security update resolves Microsoft Outlook Remote Code Execution vulnerability

Description of the security update for SharePoint Server 2016: December 9, 2025 (KB5002821)

This security update resolves Microsoft Outlook Remote Code Execution vulnerability and Microsoft Word Remote Code Execution vulnerability. To learn more about the vulnerabilities, see the following security advisories:

• Microsoft Common Vulnerabilities and Exposures CVE-2025-62562
• Microsoft Common Vulnerabilities and Exposures CVE-2025-62559​​​​​​​
• Microsoft Common Vulnerabilities and Exposures CVE-2025-62558
• Microsoft Common Vulnerabilities and Exposures CVE-2025-62555

Notes:

• This is build 16.0.5530.1000 of the security update package.
• To apply this security update, you must have the release version of Microsoft SharePoint Server 2016 installed on the computer.