Updates for SharePoint Server 2016 (January 2026 CU)

18.1.2026    |    komentáře   komentářů: 0

A new cumulative update (January 2026 CU) has been released for SharePoint Server 2016.

This CU includes both Feature Pack 2, available since the September CU (September 2017 CU), and the earlier Feature Pack 1.

SP Build:
16.0.5535.1001 (Language independent CU)
16.0.5535.1000 (Language dependent CU)

Important before installation:

If you are upgrading from the September 2025 CU to a newer update, remove the NT AUTHORITY\SYSTEM account from the local WSS_WPG and IIS_IUSRS groups on every SharePoint server in the farm before installation, if it is a member. Otherwise, installation of the update may fail.

SharePoint 2016 CU – KB articles describing the CU:

  • KB 5002828 – January 2026 Update for SharePoint Server 2016 (language independent)
  • KB 5002827 – January 2026 Update for SharePoint Server 2016 (language dependent)

SharePoint Server 2016 CU – CU download links:

After installation, remember to run the SharePoint 2016 Products Configuration Wizard or the following command:

PSConfig.exe -cmd upgrade -inplace b2b -wait -cmd applicationcontent -install -cmd installfeatures -cmd secureresources -cmd services -install

Important notes

Always install both packages in this order:

  1. language independent components (core CU)
  2. language-dependent components (language CU)

For language-dependent packages, the language you select does not matter because each package contains updates for all languages.

If you install a new language pack on a SharePoint Server 2016 farm, you must reinstall the language-dependent update afterwards.

Remember to keep Distributed Cache updated as well as SharePoint. See How to update Distributed Cache correctly (in Czech).

Note for this CU:

KB 5002828 requires farms using SharePoint Workflow Manager to install its update KB5002799 before this CU.

For 2013-type workflows, the language-dependent package KB 5002827 requires the August 2025 SharePoint Workflow Manager update to be installed first.

To keep using Classic Workflow Manager, enable its debug flag with the following commands:

$farm = Get-SPFarm
$farm.ServerDebugFlags.Add(53601)
$farm.update()
iisreset

The release version of SharePoint Server 2016 must already be installed before applying this security update.

Enabling the modern OneDrive for Business experience requires an active Software Assurance contract, whether it is enabled by installing the update or manually. If the contract is not active at that time, turn off this experience.

Included fixes and improvements

The following overview summarizes the fixes and improvements in this CU based on the official Microsoft KB articles.

SharePoint Server 2016

KB 5002828 addresses elevation of privilege in Office Click-To-Run, remote code execution in SharePoint and Word, information disclosure in SharePoint, and spoofing in SharePoint Server: CVE-2026-20943, CVE-2026-20948, CVE-2026-20963, CVE-2026-20958, CVE-2026-20951, CVE-2026-20959, CVE-2026-20947.

Language-dependent KB 5002827 addresses remote code execution in Microsoft Word: CVE-2026-20948.

The main package, KB 5002828, includes the following fix:

  • Fixes an issue where migrating Remote Blob Storage (RBS) duplicates data.

The following change in language-dependent KB 5002827 requires main package KB 5002828 as well:

  • Enables inspection of HTTP request bodies through the Antimalware Scan Interface (AMSI) in SharePoint 2016.

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