KB5002870: Fixes an issue in which the contrast between foreground and background colors
SharePoint Server 2019Microsoft
Description of the security update for SharePoint Server 2019: May 12, 2026 (KB5002870)
Summary
Important:
- If you're currently running SharePoint Workflow Manager, you must install the SharePoint Workflow Manager (KB5002799) to your farm before you install this cumulative update.
- If you're currently running the Classic version of Workflow Manager, you have to enable the debug flag in order to continue using it.
$farm = Get-SPFarm
$farm.ServerDebugFlags.Add(53601)
$farm.update()
iisreset
This security update resolves a Microsoft Word Remote Code Execution vulnerability and Microsoft SharePoint Server Remote Code Execution vulnerability. To learn more about the vulnerabilities, see the following security advisories:
- Microsoft Common Vulnerabilities and Exposures CVE-2026-40367
- Microsoft Common Vulnerabilities and Exposures CVE-2026-40365
- Microsoft Common Vulnerabilities and Exposures CVE-2026-40357
- Microsoft Common Vulnerabilities and Exposures CVE-2026-33112
- Microsoft Common Vulnerabilities and Exposures CVE-2026-33110
- Microsoft Common Vulnerabilities and Exposures CVE-2026-40368
- Microsoft Common Vulnerabilities and Exposures CVE-2026-35439
Notes:
- This is build 16.0.10417.20128 of the security update package.
- To apply this security update, you must have the release version of Microsoft SharePoint Server 2019 installed on the computer.
Improvements and fixes
This security update contains improvements and fixes for the following nonsecurity issue in SharePoint Server 2019:
- Fixes an issue in which decorative images lack alternative text or an appropriate role, causing screen readers to announce them as “graphic.” The update makes sure that decorative images are correctly marked so that they're ignored by assistive technologies, improving accessibility compliance.
- Fixes an issue in which the contrast between foreground and background colors doesn't meet WCAG 2.0 AA minimum contrast ratio thresholds. The update ensures compliance by adjusting color contrast to meet accessibility standards.
- Resolves an issue in which pages don't load because certain user controls are flagged as unsafe. After you apply this fix, you can explicitly trust the affected controls by configuring the appropriate custom farm property, (AllowedTagPrefixesWhichAreNotWebControlsList).
