The September 2026 Windows security update is now available

🚨 The Signal: Microsoft has released the September 2026 security updates for Windows, including improvements to Secure Boot certificate deployment and the servicing stack. Prompt installation is critical to maintain system integrity and protect against known vulnerabilities.

The Impact

All Windows device administrators are affected, with a high security risk if updates are not applied promptly.

  • System Administrators: Risk of unpatched vulnerabilities if updates are delayed.
  • Security Teams: Increased attack surface if patch compliance is not maintained.
  • End Users: Potential for system instability or security compromise if devices are not updated.
  • Compliance Officers: Non-compliance with mandatory patching policies and security frameworks.

The Action

  1. Review the September 2026 Windows security update release notes and associated KB articles for all relevant operating systems.
  2. Initiate deployment of the September 2026 security updates to all supported Windows devices via existing patch management solutions (e.g., Microsoft Intune, SCCM, WSUS).
  3. Monitor update deployment status and compliance across the environment to ensure successful installation.
  4. Verify the successful application of Secure Boot certificate updates on eligible devices post-patching.
  5. Report on patch compliance against internal policies and external regulatory requirements (e.g., ASD ISM, PSPF).

Domain: Intune · 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