Release Date:

9/05/2023

Version:

Security-only update

REMINDER Windows 8.1 reached end of support on January 10, 2023, at which point technical assistance and software updates is 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.

Windows Embedded 8.1 Industry Enterprise and Pro will reach end of support (EOS) on July 10, 2023. For more information, see Windows Embedded 8.1 Industry.

For Windows Server 2012 R2, the end of support (EOS) date is October 10, 2023. Extended Security Updates (ESUs) will be available for purchase no later than October 2022, but available for installation after the EOS date, October 10, 2023. ESUs 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.

Upgrade to Windows 10: FAQ Learn more about upgrading Windows Server

Summary

Learn more about this security-only 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, please see the following article. To view other notes and messages, see the Windows 8.1 and Windows Server 2012 R2 update history home page.

Improvements

This update makes improvements for the following issues:

  • By order of the Islamic Republic of Iran on September 22, 2022, daylight saving time (DST) will no longer be observed and the republic will remain on Iran Standard Time UTC+03:30.

  • Local Kerberos authentication fails if the local Key Distribution Center (KDC) service is stopped. Additionally, all local Kerberos logons fail with the error STATUS_NETLOGON_NOT_STARTED.

  • After the Windows Security-only update dated November 8, 2022, is installed, Kerberos constrained delegation (KCD) fails with the error message KRB_AP_ERR_MODIFIED on Read/Write Domain Controllers.

For more information about the resolved security vulnerabilities, please refer to the Deployments | Security Update Guide and the May 2023 Security Updates.

Known issues in this update

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

How to get this update

Before installing this update

We strongly recommend that you install the latest servicing stack update (SSU) for your operating system before you install the latest security-only update. SSUs improve the reliability of the update process to mitigate potential issues while installing the security-only update 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 (KB5023790) will be offered to you automatically. To get the standalone package for the latest SSU, search for it in the Microsoft Update Catalog.

REMINDER If you are using Security-only updates, you will also need to install all previous Security-only updates and the latest cumulative update for Internet Explorer (KB5026366).

Language packs

If 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.

Learn about adding a language pack to Windows

Install this update

Release Channel

Available

Next Step

Windows Update and Microsoft Update

No

See the other options below.

Microsoft Update Catalog

Yes

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

Windows Server Update Services (WSUS)

Yes

This update will automatically sync with WSUS if you configure Products and Classifications as follows:

Product: Windows Server 2012 R2, Windows Embedded 8.1 Industry Enterprise, Windows Embedded 8.1 Industry Pro

Classification: Security Update

File information

For a list of the files that are provided in this update, download the file information for update KB5026409.

References

Learn about the standard terminology that is used to describe Microsoft software updates.

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