Updates for SharePoint Server 2019 (May 2026 CU)

17.5.2026    |    komentáře   komentářů: 0

A new cumulative update (May 2026 CU) has been released for SharePoint Server 2019.

SP Build:
16.0.10417.20128 (Language independent CU)
16.0.10417.20128 (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 2019 CU – KB articles describing the CU:

  • KB 5002870 – May 2026 Update for SharePoint Server 2019 (language independent)
  • KB 5002872 – May 2026 Update for SharePoint Server 2019 (language dependent)

SharePoint Server 2019 CU – CU download links:

After installation, remember to run the SharePoint 2019 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 2019 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 5002870: Farms using SharePoint Workflow Manager need KB 5002799 installed before this CU.

KB 5002872: If the farm runs 2013-type workflows, install the August 2025 SharePoint Workflow Manager update before this CU.

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

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

The release version of SharePoint Server 2019 must already be installed.

Included fixes and improvements

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

SharePoint Server 2019

KB 5002870 addresses remote code execution vulnerabilities in Word and SharePoint Server. The advisories are CVE-2026-40367, CVE-2026-40365, CVE-2026-40357, CVE-2026-33112, CVE-2026-33110, CVE-2026-40368, CVE-2026-35439.

KB 5002872 also addresses remote code execution in Word under CVE-2026-40367.

The following nonsecurity fixes are listed for core KB 5002870 and language KB 5002872; each item identifies its package:

  • KB 5002870 and KB 5002872: Fixes an issue where missing alternative text or an appropriate role makes screen readers announce decorative images as “graphic.” Correct marking lets assistive technologies skip these images and improves accessibility compliance.

  • KB 5002870 and KB 5002872: Fixes an issue where foreground and background colors fall short of the minimum contrast ratios required by WCAG 2.0 AA. The update adjusts those colors to meet the accessibility thresholds.

  • KB 5002870: Fixes an issue where pages fail to load after some user controls are classified as unsafe. After installation, the affected controls can be explicitly trusted through the custom farm property AllowedTagPrefixesWhichAreNotWebControlsList.

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