JPCERT-AT-2026-0001
JPCERT/CC
2026-01-14

I. Overview

Microsoft has released January 2026 Security Updates to address the vulnerabilities in their products. Remote attackers leveraging these vulnerabilities may be able to execute arbitrary code.

Microsoft Corporation
January 2026 Security Updates
https://msrc.microsoft.com/update-guide/en-us/releaseNote/2026-Jan

According to Microsoft, among the vulnerabilities, the following vulnerability has been confirmed to be exploited in the wild. Please consider applying the security update programs by referring to the information provided by Microsoft.

CVE-2026-20805
Desktop Window Manager Information Disclosure Vulnerability
https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-20805

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 (Early Warning Group)
MAIL: ew-info@jpcert.or.jp
https://www.jpcert.or.jp/english/