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: ew-info@jpcert.or.jp
https://www.jpcert.or.jp/english/