MC1150558 – The September 2025 Windows security update is now available

Product:

SharePoint, Windows, Windows Server

Platform:

Online, Windows Desktop, World tenant

Status:

Change type:

Admin impact

Links:

Details:

The September 2025 security update is now available for all supported versions of Windows. We recommend that you install these updates promptly. For more information about the contents of this update, see the release notes, which are easily accessible from the Windows 11 and Windows 10 update history pages. To learn more about the different types of monthly quality updates, see Windows monthly updates explained.

Highlights for the Windows 11, version 24H2 update:
This security update includes improvements that were a part of update KB5064081 (released August 29, 2025).
This update makes quality improvements to the servicing stack, which is the component that installs Windows updates.
This update addresses an issue that caused non-admin users to receive unexpected User Account Control (UAC) prompts when MSI installers perform certain custom actions.
This update enables auditing Server Message Block (SMB) client compatibility for SMB Server signing as well as SMB Server Extended Protection for Authentication (EPA). This allows customers to assess their environment before deploying the hardening measures that are already supported by SMB Server.
This update addresses an issue that affects audio in apps using the Network Device Interface (NDI).


Short on time? Watch our Windows 11 release notes video for this month's tips.


Note: To address an issue with Windows Powershell PSDirect connections, Microsoft recommends applying the September 2025 security update for Windows PowerShell in hotpatched devices.
KB5066360 - Windows Server 2025 Datacenter: Azure Edition
KB5066360 - Windows 11 Enterprise LTSC 2024
KB5066359 - Windows Server 2022 Datacenter: Azure Edition


For instructions on how to install this update, see the KB for your operating system listed below:
Windows 11, version 24H2: KB5065426
Windows 11, versions 23H2 and 22H2: KB5065431
Windows 11 Enterprise LTSC 2024: Hotpatch KB5065474
Windows 10, versions 22H2 and 21H2: KB5065429
Windows 10 Enterprise LTSC 2019 and Windows Server 2019: KB5065428
Windows 10 LTSB 2016 and Windows Server 2016: KB5065427
Windows 10 LTSB 2015: KB5065430
Windows Server 2025: KB5065426
Windows Server 2025 Datacenter: Azure Edition: Hotpatch KB5065474
Windows Server 2022: KB5065432
Windows Server 2022 Datacenter: Azure Edition: Hotpatch KB5065306
Windows Server 2012 R2: Monthly Rollup: KB5065507
Windows Server 2012: Monthly Rollup: KB5065509
Windows Server 2008 R2 Service Pack 1: Monthly Rollup: KB5065468 / Security Only: KB5065510
Windows Server 2008 SP2: Monthly Rollup: KB5065508 / Security Only: KB5065511

Change Category:
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Release Phase:

Created:
2025-09-10

updated:
2025-09-10

Task Type

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Docu to Check

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MS Preperations

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summary for non-techies**

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Direct effects for Operations**

Unexpected User Account Control (UAC) Prompts
Non-admin users may experience unexpected UAC prompts when using MSI installers, leading to confusion and potential delays in workflow.
   - roles: End Users, IT Support
   - references: https://support.microsoft.com/help/5064081, https://support.microsoft.com/help/5065426

Audio Issues in Applications
Applications using the Network Device Interface (NDI) may face audio issues, impacting user experience during meetings or presentations.
   - roles: End Users, Application Developers
   - references: https://support.microsoft.com/help/5064081, https://support.microsoft.com/help/5065426

SMB Client Compatibility Auditing
Without preparation, organizations may struggle with assessing their environment for SMB Server signing and Extended Protection for Authentication, leading to security vulnerabilities.
   - roles: Network Administrators, Security Officers
   - references: https://support.microsoft.com/help/5064081, https://support.microsoft.com/help/5065426

Servicing Stack Improvements
Failure to implement the servicing stack improvements may result in issues with future updates, causing system instability and downtime.
   - roles: System Administrators, IT Operations
   - references: https://support.microsoft.com/help/5064081, https://support.microsoft.com/help/5065426

PowerShell Connection Issues
Not applying the update may lead to issues with Windows PowerShell PSDirect connections, affecting automation and scripting tasks.
   - roles: DevOps Engineers, System Administrators
   - references: https://support.microsoft.com/help/5064081, https://support.microsoft.com/help/5065426

Configutation Options**

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IT Security**

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explanation for non-techies**

The latest Windows security update for September 2025 is now available, and it's important to understand why these updates matter. Think of these updates like a regular car maintenance check. Just as you wouldn't want to drive a car with worn-out brakes or a faulty engine, you don't want your computer systems running on outdated software that could have vulnerabilities. These updates are designed to fix issues and improve the overall performance and security of your systems.

This particular update brings several improvements. For instance, it addresses a problem where non-admin users were unexpectedly asked for permission to perform certain actions, much like how a security guard might mistakenly stop you every time you enter your own office. By fixing this, the update ensures smoother operations without unnecessary interruptions.

Additionally, the update enhances security measures for network communications, similar to upgrading the locks on your office doors to ensure only authorized personnel can enter. This helps protect sensitive information and maintain a secure environment.

For those using specific applications that rely on audio through network connections, this update also resolves issues that could affect sound quality, ensuring that everything works as it should, much like ensuring the conference room speaker system is clear and functional for meetings.

To implement these updates, you can follow the instructions provided for your specific version of Windows or Windows Server. It's akin to following a step-by-step guide to ensure your car's maintenance is done correctly, keeping everything running smoothly and safely.

For those short on time, there's a video available that highlights the key points of this update, much like a quick briefing session that gives you the essentials without going into too much detail. This can be particularly useful for busy professionals who need to stay informed without delving into technical specifics.

In summary, keeping your systems updated is crucial for maintaining security and efficiency, much like regular maintenance is essential for a reliable and safe vehicle. By staying on top of these updates, you ensure that your technology infrastructure remains robust and protected against potential threats.