KB5002834: Fixes an issue in which the w3wp process stops responding repeatedly.

Description of the security update for SharePoint Server 2019: February 10, 2026 (KB5002834)

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

• Microsoft Common Vulnerabilities and Exposures CVE-2026-21511
• Microsoft Common Vulnerabilities and Exposures CVE-2026-21260

Improvements and fixes
This security update contains improvements and fixes for the following nonsecurity issue in SharePoint Server 2019:

• Fixes the GB18030-2022 China certification issue.
• Fixes an issue in which the w3wp process stops responding repeatedly.
• Fixes an issue in which Set-SPMachineKey can no longer be used to set machine keys after the September 2025 cumulative update is installed.