August 13, 2024—KB5041571 (OS Build 26100.1457)

For information about Windows update terminology, see the article about the types of Windows updates and the monthly quality update types. NoteFollow @WindowsUpdate to find out when new content is published to the Windows release health dashboard.

**Important:**Windows 11, version 24H2 is targeting Copilot+ PCs devices and devices that were previously using Windows Insider 24H2 builds.

Highlights

• This update addresses security issues for your Windows operating system.

Improvements

This security update includes improvements that were a part of update KB5040529 (released July 23, 2024). Below is a summary of the key issues that this update addresses when you install this KB. If there are new features, it lists them as well. The bold text within the brackets indicates the item or area of the change we are documenting.

• [Lock screen] This update addresses CVE-2024-38143. Because of this, the “Use my Windows user account” checkbox is not available on the lock screen to connect to Wi-Fi.
• [NetJoinLegacyAccountReuse] This update removes this registry key. For more information refer to KB5020276—Netjoin: Domain join hardening changes.
• **[Secure Boot Advanced Targeting (SBAT) and Linux Extensible Firmware Interface (EFI)]**This update applies SBAT to systems that run Windows. This stops vulnerable Linux EFI (Shim bootloaders) from running. This SBAT update will not apply to systems that dual-boot Windows and Linux. After the SBAT update is applied, older Linux ISO images might not boot. If this occurs, work with your Linux vendor to get an updated ISO image.
• [Domain Name System (DNS)] This update hardens DNS server security to address CVE-2024-37968. If the configurations of your domains are not up to date, you might get the SERVFAIL error or time out.
  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 Security Update Guide website and the August 2024 Security Updates.

Windows 11 servicing stack update (KB5041575)- 26100.1440

This update makes quality improvements to the servicing stack, which is the component that installs Windows updates. Servicing stack updates (SSU) ensure that you have a robust and reliable servicing stack so that your devices can receive and install Microsoft updates.

Known issues in this update

Applies to	Symptom	Workaround
All users	We’re aware of an issue where players on Arm devices are unable to download and play Roblox via the Microsoft Store on Windows.	Players on Arm devices can play Roblox by downloading the title directly from www.Roblox.com.

How to get this update

Before you install this updateMicrosoft combines the latest servicing stack update (SSU) for your operating system with the latest cumulative update (LCU). For general information about SSUs, see Servicing stack updates and Servicing Stack Updates (SSU): Frequently Asked Questions.Install this updateTo install this update, use one of the following Windows and Microsoft release channels.

Windows UpdateBusinessCatalogServer Update Services

Available	Next Step
Yes	None. This update will be downloaded and installed automatically from Windows Update and Microsoft Update.

Available	Next Step
Yes	None. This update will be downloaded and installed automatically from Windows Update for Business in accordance with configured policies.

Available	Next Step
Yes	To get the standalone package for this update, go to the Microsoft Update Catalog website.

Available	Next Step
Yes	This update will automatically sync with Windows Server Update Services (WSUS) if you configure Products and Classifications as follows:Product: Windows 11Classification: Security Updates

If you want to remove the LCUTo remove the LCU after installing the combined SSU and LCU package, use the DISM/Remove-Package command line option with the LCU package name as the argument. You can find the package name by using this command:DISM /online /get-packages.Running Windows Update Standalone Installer (wusa.exe) with the**/uninstall **switch on the combined package will not work because the combined package contains the SSU. You cannot remove the SSU from the system after installation.

File informationFor a list of the files that are provided in this update, download the file information for cumulative update 5041571. For a list of the files that are provided in the servicing stack update, download the file information for the SSU (KB5041575) - version 26100.1440.