Microsoft has just released a critical extended security update for Windows 10, addressing not only this month’s record-breaking September 2026 Patch Tuesday fixes but also several bugs and vulnerabilities. The update, KB5122878, is specifically designed to patch 966 flaws across Microsoft’s products, including two actively exploited zero-day vulnerabilities. If you’re running the Enterprise LTSC version of Windows 10 or have enrolled in the Extended Security Update (ESU) program, this update should be automatically available for download and installation.
The KB5122878 update is primarily a security-focused release, with no new features added to Windows 10. Instead, it includes a list of fixes that address various issues across multiple components of the operating system. One notable change in this update is the addition of high-confidence device targeting data, which enhances the coverage of devices eligible for automatic Secure Boot certificate updates. This feature aims to provide an additional layer of security by ensuring that only trusted devices can boot up and run Windows 10.
Another fix included in this release addresses an issue with Remote Desktop audio redirection. Previously, audio from remote sessions might not play on the local computer in certain configurations, but this update resolves that problem. Additionally, the KB5122878 update improves logging features for the OMA DM Client component and recognizes Microsoft Windows Production PCA 2026 RSA2048-SHA256 as equivalent to PCA 2011 during Windows certificate-authority rotation.
The September 2026 Patch Tuesday fixes marked a record-breaking month for Microsoft, with 966 vulnerabilities patched across its products. This includes two actively exploited zero-day flaws that have been addressed in the KB5122878 update. While it’s unclear what specific vulnerabilities are being fixed, it’s essential to note that this release should be prioritized by users who rely on Windows 10 for critical operations.
It’s also worth noting that Microsoft has stated there are no known issues with this update. As with any software patch, it’s recommended to carefully review the system requirements and ensure that all updates are applied in a controlled environment before deploying them to your organization.
To protect yourself from potential security threats, it’s essential to stay up-to-date on the latest patches and updates for your operating system. By installing this update as soon as possible, you’ll be ensuring that your Windows 10 installation is patched against known vulnerabilities and bugs. If you’re not running the Enterprise LTSC version or are not enrolled in the ESU program, it’s recommended to consult with a Microsoft support specialist or IT administrator to determine the best course of action for updating your system.
Source: Bleeping Computer — 2026-09-08