September's Windows 11 patch needs an emergency patch of its own

Microsoft has released a follow-up patch for Windows 11's September update, needed due to issues arising from the large-scale security fix. Over 1,000 vulnerabilities were addressed, but new problems emerged, primarily affecting USB Audio Class 1.0 devices, Remote Desktop Services, and host folders shared with specific Linux virtual machines.

The Hyper-V and Remote Desktop Services problems have been resolved, yet concerns remain regarding USB audio devices. These devices might still be silent, have unresponsive volume controls, or display an error message stating "This device cannot start (Code 10)" in Device Manager. Microsoft has acknowledged the issue and assured owners that they are actively working on a solution.

The cumulative update also includes safeguards against a separate elevation-of-privilege vulnerability, identified as CVE-2026-62721, in the Windows User-Mode Power Service. However, separate security updates for Excel versions have inadvertently broken the Paste function for some installations, prompting user support for Microsoft's patching efforts despite the unintended consequences.