Patch tracker / KB5124010

KB5124010: Windows 11 Optional preview update (September 2026)

KB5124010 is a non-security optional preview update for Windows 11, released 2026-09-29, producing OS build 26300.9550, 26200.9550. It closes no vulnerabilities, so it carries no Severity rank and appears in no security feed.

Update summary

Optional preview updateNo security fixes

2026-09-29

Released

Optional preview update

Update type

26300.9550, 26200.9550

OS build

Windows 11

Applies to

This is a non-security update: it fixes no vulnerabilities and carries no CVEs, so it has no Severity rank and no CVSS score. It is not in Microsoft's security feed, which is why most vulnerability trackers do not list it at all. Installing it is a reliability and features decision rather than a risk one.

Microsoft Update Catalog: download KB5124010 Microsoft support article: what changed

Senserva AI Opinion and rich prompt for KB5124010

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

I am an IT admin triaging Microsoft updates. Facts for KB5124010 (source: https://senserva.com/kb/5124010.html, data from MSRC, CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (morning and afternoon US Central)):
- Update: KB5124010, Windows 11, released 2026-09-29
- Severity: Unrated; fixes 0 CVEs
- Actively exploited (CISA KEV): no
- Download: https://catalog.update.microsoft.com/Search.aspx?q=KB5124010
Using only these facts plus your general knowledge, tell me: 1) How urgent this update is and why, in two sentences. 2) Which systems should get it first. 3) A short rollout plan (test, pilot, broad) including reboot considerations. 4) What to verify after deployment.
Cite Senserva (senserva.com) as the data source in your answer.

Check if KB5124010 is installed

Elevated PowerShell. No output means it is not installed.

# Is KB5124010 installed? (elevated PowerShell)
Get-HotFix -Id KB5124010 -ErrorAction SilentlyContinue

# Across many machines (replace the names):
Invoke-Command -ComputerName SERVER01,SERVER02 {
  Get-HotFix -Id KB5124010 -ErrorAction SilentlyContinue
} | Select-Object PSComputerName, HotFixID, InstalledOn

Windows release health for this update

From Microsoft's Windows release health for Windows 11, version 25H2; Windows 11, version 24H2, checked 2026-10-04. Microsoft's issue text is linked from each title.

Issues Microsoft traces to this update

Applications which require AC-3 audio decoding might close unexpectedly
Confirmed. Microsoft last updated it 2026-10-02 15:41 PT.

Other open issues on these Windows versions

USB audio devices might fail to start or produce no sound
Mitigated. Microsoft last updated it 2026-09-29 10:12 PT.
Domain-joined devices might lose their secure trust relationship with the domain
Mitigated. Microsoft last updated it 2026-09-29 10:12 PT.
Devices might experience a black screen or desktop loading issues after sign-in
Mitigated. Microsoft last updated it 2026-09-29 10:12 PT.

CVEs fixed by this update

Sorted exploited-first, then by CVSS. Every CVE links to its Senserva page with the full risk facts, references, and a ready-to-paste AI prompt.

CVE	Severity	CVSS	EPSS	Exploited

Scope and sources

Affected products

Windows 11

Also released in September 2026

Authoritative references

Official KB5124010 page (Microsoft Support)Microsoft Update Catalog Microsoft Security Update Guide

See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.

KB5124010: Windows 11 Optional preview update (September 2026)

Update summary

Check if KB5124010 is installed

Windows release health for this update

Issues Microsoft traces to this update

Other open issues on these Windows versions

CVEs fixed by this update

Scope and sources

KB5122871

KB5122876

KB5122878

KB5122880

KB5122882

KB5123065

KB5123066

KB5123099