Security Alert: Microsoft Releases September 2026 Security Updates

JPCERT-AT-2026-0025 JPCERT/CC 2026-09-09 I. Overview Microsoft has released September 2026 Security Updates to address the vulnerabilities in their products. Attackers leveraging these vulnerabilities may be able to execute arbitrary code remotely without authentication or elevate privileges locally after authentication, etc. Microsoft Corporation September 2026 Security Updates https://msrc.microsoft.com/update-guide/en-US/releaseNote/2026-Sep According to Microsoft, among the vulnerabilities, the following vulnerability has been confirmed to be exploited in the wild. Please refer to the latest information provided by Microsoft and implement the measures described in "II. Solution." CVE-2026-85880 Windows Advanced Local Procedure Call (ALPC) Elevation of Privilege Vulnerability https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85880 CVE-2026-81963 Windows Update Stack Elevation of Privilege Vulnerability https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-81963 II. Solution Please apply the security update programs through Microsoft Update, Windows Update, etc. Microsoft Update Catalog https://www.catalog.update.microsoft.com/ Windows Update: FAQ https://support.microsoft.com/en-us/help/12373/windows-update-faq III. References Microsoft Corporation Release Notes https://msrc.microsoft.com/update-guide/ If you have any information regarding this alert, please contact JPCERT/CC. JPCERT Coordination Center (Cyber Security Coordination Group) MAIL: [email protected] https://www.jpcert.or.jp/english/