May 14, 2024—KB5037823 (Monthly Rollup)

IMPORTANT The installation of this Extended Security Update (ESU) might fail when you try to install it on an Azure Arc-enabled device that is running Windows Server 2012 R2. For a successful installation, please make sure all Subset of endpoints for ESU only are met as described in Connected Machine agent network requirements.

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End of support information

• Windows 8.1 reached the end of support (EOS) on January 10, 2023, at which point technical assistance and software updates are no longer provided. If you have devices running Windows 8.1, we recommend upgrading them to a more current, in-service, and supported Windows release. If devices do not meet the technical requirements to run a more current release of Windows, we recommend that you replace the device with one that supports Windows 11.Microsoft will not be offering an Extended Security Update (ESU) program for Windows 8.1. Continuing to use Windows 8.1 after January 10, 2023 may increase an organization’s exposure to security risks or impact its ability to meet compliance obligations. For more information, see Windows 8.1 support will end on January 10, 2023.We recommend upgrading to a later version of Windows. For more information, see Upgrade to a later version of Windows.
• Windows Server 2012 R2 reached the end of support (EOS) on October 10, 2023. Extended Security Updates (ESUs) are available for purchase and will continue for three years, renewable on an annual basis, until the final date on October 13, 2026. For more information, see Windows Server End of Support: Key Dates. For information about the procedure to continue receiving security updates, see KB5031043.

We recommend upgrading to a later version of Windows Server. For more information, see Overview of Windows Server upgrades.

• Windows Embedded 8.1 Industry Enterprise and Windows Embedded 8.1 Industry Pro reached the end of support (EOS) on July 11, 2023. Therefore, technical assistance and software updates are no longer provided.

Summary

Learn more about this cumulative security update, including improvements, any known issues, and how to get the update.

NOTE For information about the various types of Windows updates, such as critical, security, driver, service packs, and so on, see Description of the standard terminology that is used to describe Microsoft software updates. To view other notes and messages, see the Windows 8.1 and Windows Server 2012 R2 update history home page.

Improvements

This cumulative security update includes improvements that are part of update KB5036960 (released April 9, 2024). This update also includes the following improvements:

• Croatia currency is changed from Krona to Euro.
• Starting with this update, Next Secure 3 (NSEC3) validation in a Recursive Resolver (also known as a DNS recursor) will be limited to 1,000 computations. Validation of one label with one iteration is considered as one computation. DNS server administrators can change the default number of computations for this validation in their environment by setting the following registry value.Registry key| HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DNS\Parameters\
  —|—
  Type| DWORD Value name| MaxComputationForNsec3Validation Value data| 1000 (default value)Minimum value: 1Maximum value: 9600
• Resolves the following known issues after installing the update released April 9, 2024 (KB5036960):
  • A Domain Controller might experience an unexpectedly high NTLM authentication load.
  • Your VPN connection might fail.
    For more information about the resolved security vulnerabilities, please refer to the Deployments | Security Update Guide and the May 2024 Security Updates.

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Known issues in this update

We are currently not aware of any issues with this update.

How to get this update

Before installing this updateWe strongly recommend that you install the latest servicing stack update (SSU) for your operating system before you install the latest Monthly Rollup. SSUs improve the reliability of the update process to mitigate potential issues while installing the Monthly Rollup and applying Microsoft security fixes. For general information about SSUs, see Servicing stack updates and Servicing Stack Updates (SSU): Frequently Asked Questions.If you use Windows Update, the latest SSU (KB5037021) will be offered to you automatically. To get the standalone package for the latest SSU, search for it in the Microsoft Update Catalog.Language packsIf you install a language pack after you install this update, you must reinstall this update. Therefore, we recommend that you install any language packs that you need before you install this update. For more information, see Learn about adding a language pack to Windows.Install this updateTo install this update, use one of the following release channels.

Windows UpdateUpdate CatalogServer Update Services

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

Available	Next Step
Yes	To get the standalone package for this update, go to the Microsoft Update Catalog website.To download updates from the Update Catalog, see Steps to download updates from the Windows Update Catalog.

Available	Next Step
Yes	This update will automatically sync with WSUS if you configureProducts and Classifications as follows:Product: Windows Server 2012 R2Classification: Security UpdatesFor more information, see Configure classifications and products to synchronize.

File information

For a list of the files that are provided in this update, download the file information for update KB5037823.