New Update Windows 11 October 2026 Patch Tuesday (KB5127648, KB5127646)

Windows 11
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Gandalf_The_Grey

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Microsoft has released the October 2026 Patch Tuesday updates for Windows 11 26H2, 26H1, 25H2, and 24H2. Windows 11 26H2, 25H2, and 24H2 are getting KB5127648, which moves those versions to builds 26300.9711, 26200.9711, and 26100.9711, respectively.

Windows 11 26H1 is getting a separate KB5127646 update, which bumps the build number to 28000.3231 on Arm64 systems.

The updates are now available through Windows Update and the Microsoft Update Catalog. Microsoft has not published the full changelogs yet, so we’ll update this article once the detailed release notes are available.
 
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Thanks, Gandalf. One important detail for anyone still on Windows 11 24H2 Home or Pro: October 13 is its end-of-servicing date, so KB5127648 should be its final scheduled security update. Enterprise and Education editions remain supported until October 2027. Microsoft lists the current lifecycle dates here.

The shared KB for 24H2, 25H2 and 26H2 reflects their closely related servicing base, while 26H1 remains on the separate 28000 build branch. These are cumulative updates, so previously released fixes are included; there is no need to install September’s preview first.

After restarting, winver should report the appropriate build:

  • 26H2: 26300.9711
  • 25H2: 26200.9711
  • 24H2: 26100.9711
  • 26H1: 28000.3231

Anyone using 24H2 Home/Pro should plan the feature upgrade rather than treating this month’s patch as a long-term stopping point. For less adventurous systems, it is also sensible to watch Microsoft’s release-health pages for newly acknowledged issues before deploying broadly.
 
The updates are now available through Windows Update and the Microsoft Update Catalog. Microsoft has not published the full changelogs yet, so we’ll update this article once the detailed release notes are available.
Here are the changes:
Here's whats new in the KB5127648 update:

  • [Security updates] This update provides security improvements. For more information about the security vulnerabilities resolved by this update, see the Security Update Guide.
  • [Secure Boot] This update continues the deployment of updated Secure Boot certificates using the latest high-confidence targeting data to identify eligible devices that are ready to automatically receive the new certificates. Deployment through Windows Update remains ongoing across supported devices.
  • [Windows Explorer (Known issue)] Fixed This update fixes an issue that affects Windows Explorer in multi-user environments, such as Azure Virtual Desktop and FSLogix. After sign-in, Explorer.exe might fail to start or repeatedly crash, causing a black screen.
  • [Audio (known issue)] Fixed This update fixes an issue that affects AC-3 audio playback in some applications.
  • [Always On VPN] This update fixes an issue that affects Always On VPN connections after installing KB5124008. When automatic protocol selection or protocol fallback was configured, affected VPN connections could remain stuck in a Connecting state or fail to connect after an initial connection attempt failed. In some cases, subsequent connection attempts could display the error, "The specified port is already in use."
  • [Storage Spaces] This update fixes an issue that affects tiered Storage Spaces Direct virtual disks. Some virtual disks might fail to come online after installing certain security updates, making dependent clustered workloads unavailable.
  • [Date and Time] This update introduces the new (UTC-05:00) Manitoba time zone to support Manitoba’s November 1, 2026, time zone change.
  • [ReFS security] This update adds auditing and optional policy controls for ReFS volumes on externally attached storage devices. Auditing is enabled by default, while enforcement controls remain disabled by default to give administrators time to evaluate and prepare for future security hardening changes. To learn more, see KB5130741.
  • [Printing] This update resolves an issue where printing could fail in some applications and on devices using RAW or Generic Text Only printer drivers after installing the August 2026 security update.
  • [Gaming] This update fixes an issue that could cause mouse input to stutter in some games.
  • [Windows Hello] This update fixes an issue where fingerprint sign-in might not work after a cold boot on some devices.
 

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