May 12, 2026—KB5087537 (OS Build 14393.9140)

Windows Secure Boot certificate expiration

Important: Secure Boot certificates used by most Windows devices are set to expire starting in June 2026. This might affect the ability of certain personal and business devices to boot securely if not updated in time. To avoid disruption, we recommend reviewing the guidance and taking action to update certificates in advance.

For details and preparation steps for Windows devices, see Windows Secure Boot certificate expiration and CA updates.

For details and preparation steps for Windows servers, see the following resources:

Summary

This article lists the security issues and quality improvements included in this cumulative security update.

Applies to: Windows Server 2016

This security update includes fixes and improvements that are a part of the following update:

The following is a summary of the issues that this update addresses. The bold text within the brackets indicates the item or area of the change we are documenting.

[Remote Desktop security warnings (known issue)] Fixed: The Remote Desktop Connection security warning dialog might render incorrectly in multi-monitor configurations with different display scaling settings. This issue might occur after installing the Windows security update released on or after April 14, 2026 (such as KB5082198).
[Sign-In] Fixed: After you install the Windows update released on or after March 10, 2026, some users might experience an issue signing in to apps with a Microsoft account. Even when the device has a working Internet connection, a “no Internet” error appears during sign in and prevents access to Microsoft services and apps such as Microsoft Teams.
[Daylight Savings Time (DST)] Update for Arab Republic of Egypt to support the government DST change order in 2023.
[Secure Boot] With this update, Windows quality updates include additional high confidence device targeting data, increasing coverage of devices eligible to automatically receive new Secure Boot certificates. Devices receive the new certificates only after demonstrating sufficient successful update signals, maintaining a controlled and phased rollout.

If you installed earlier updates, only the new updates contained in this package will be downloaded and installed on your device.

For more information about security vulnerabilities, please refer to the new Security Update Guide website and the May 2026 Security Updates.

For more information about Windows 10, version 1607, see its update history page.

For information about Windows update terminology, see the article about the types of Windows updates and the monthly quality update types.

Known issues in this update

Microsoft is not currently aware of any issues with this update.

How to get this update

Before you install this update

To install updates released on or after January 14, 2025, we recommend you first install the latest Servicing Stack Update (SSU). If your device or offline image does not have the latest SSU installed, you might not be able to install this update.

Caution Until you install the SSU, this update might not be offered to your device. To reduce your security risk, install the SSU as soon as possible.

If you use Windows Update, the latest SSU (KB5088064) will be offered to you automatically. If the latest SSU is not installed, you might not be able to install this update.
If you use Windows Update for Business, the latest SSU (KB5088064) will be offered to you automatically. If the latest SSU is not installed, you might not be able to install this update.
If you use the Update Catalog, we recommend you download and install the latest SSU (KB5088064). If the latest SSU is not installed, you might not be able to install this update.
If you are a Windows Server Update Services (WSUS) administrator, you must approve SSU KB5088064 and this update KB5087537.

For general information about SSUs, see Servicing stack updates.

Get and install this update

To get and install this update, use one of the following Windows and Microsoft release channels.

Available	Next Step
	This update will be downloaded and installed automatically from Windows Update.

File information

A list of the files that are included in this update are provided in a CSV (Comma delimited) (*.csv) file. The file can be opened in a text editor such as Notepad or in Microsoft Excel.

Note: The English (United States) version of this software update might contain files for additional languages.

Download Icon Download the file information for this cumulative update KB5087537.