Take Action: Out-of-band update released to address issues from the September 2026 Windows security update

🚨 The Signal: Microsoft released an out-of-band Windows update to fix critical issues from the September 2026 security update. These fixes address Hyper-V, Remote Desktop, and USB audio problems, restoring system stability and access.

The Impact

Windows users and administrators are affected by critical system and access issues, posing a significant operational and security risk.

  • Hyper-V users: Host folder shares may be unavailable, disrupting virtual machine operations.
  • Remote Desktop users: Sessions may stop responding, preventing new connections and sign-ins.
  • All users: System instability and access issues can lead to productivity loss.
  • Administrators: Required to deploy an urgent out-of-band update to restore services.

The Action

  1. Verify Windows Update for Business policies ensure automatic deployment of OOB updates.
  2. For WSUS environments, confirm the OOB update (KB number) has synced and is approved for deployment.
  3. Manually apply the OOB update from the Microsoft Update Catalog for critical systems not managed by automated tools.
  4. For hotpatch-enabled devices, ensure the September 2026 security update is installed to receive the OOB hotpatch automatically.

Domain: Other · Impact: high · Workload: Other · Essential Eight: Patch Operating Systems · ISM: ISM-1407, ISM-1501, ISM-1621, ISM-1622, ISM-1623, ISM-1654, ISM-1655, ISM-1694, ISM-1695, ISM-1696, ISM-1701, ISM-1702, ISM-1877, ISM-1889, ISM-1902