Patch tracker / KB5129242

KB5129242: Windows 11 Out-of-band update (September 2026)

KB5129242 is a non-security out-of-band update for Windows 11, released 2026-09-14, producing OS build 22631.7584. It closes no vulnerabilities, so it carries no Severity rank and appears in no security feed.

Before you deploy: Microsoft lists 1 known issue for this update.

Known issues

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Update summary

Out-of-band updateNo security fixes
2026-09-14
Released
Out-of-band update
Update type
22631.7584
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.

Senserva found thiswe track every release for this product line, so we can tell you this package is behind

A newer security update for Windows 11 has shipped since this one: KB5124010 (2026-09-29). For cumulative update families the newer package includes these fixes, so installing that one is usually the shorter path. Verify against your own update rings before you skip this package.

Senserva found thisread these before you deploy broadly

Microsoft documents 1 known issue with this update.

  • USB Audio Class 1.0 devices with error Code 10 or no output

The full text, quoted from Microsoft

Microsoft Update Catalog: download KB5129242Microsoft support article: what changed
Senserva AI Opinion and rich prompt for KB5129242

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Check if KB5129242 is installed

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Known issues, from Microsoft

Quoted from Microsoft's support article for KB5129242 (checked 2026-09-15). Microsoft lists 1 known issue. Verify against the article before acting.

USB Audio Class 1.0 devices with error Code 10 or no output

Symptoms

After installing the September 8, 2026, Windows security update, some USB Audio Class 1.0 devices might fail to start or produce audio. Affected devices might experience one or more of the following symptoms:

The device displays an error in Device Manager: "This device cannot start (Code 10).”

No audio output.

Volume controls are unresponsive or remain at zero.

Sound settings are unresponsive or unavailable.

This issue is limited to USB Audio Class 1.0 devices.

Resolution

Microsoft is working on a resolution and will update this documentation when more information is available.

From the Senserva blog

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.

CVESeverityCVSSEPSSExploited

Scope and sources

Affected products
Also released in September 2026

KB5122871

684 CVEs · Critical · exploited

KB5122876

620 CVEs · Critical · exploited

KB5122878

572 CVEs · Critical · exploited

KB5122880

608 CVEs · Critical · exploited

KB5122882

645 CVEs · Critical · exploited

KB5123065

398 CVEs · Critical · exploited

KB5123066

423 CVEs · Critical · exploited

KB5123099

559 CVEs · Critical · exploited

The full month, summarized: Microsoft Patch Tuesday.

Authoritative references
Official KB5129242 page (Microsoft Support)Microsoft Update CatalogMicrosoft Security Update Guide

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

New to a term on this page? CVE, KB, KEV, CVSS, and EPSS are each explained once, on the Senserva security lexicon. Reference: Microsoft CVE and vulnerability management and the Microsoft patching guide.
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