Description:
Microsoft has released security updates addressing multiple vulnerabilities which affect several Microsoft products or components. The list of security updates can be found at:
https://msrc.microsoft.com/update-guide/releaseNote/2026-Jan
Reports indicated that an information disclosure vulnerability (CVE-2026-20805) in Microsoft Windows is being exploited in the wild. In addition, a security restriction bypass vulnerability (CVE-2026-21265) in Windows Secure Boot is considered publicly disclosed. Microsoft has released security updates to address the issues. System administrators and users are advised to take immediate action to patch your affected systems to mitigate the elevated risk of cyber attacks.
Affected Systems:
- Microsoft Windows 10, 11
- Microsoft Windows Server 2008, 2008 R2, 2012, 2012 R2, 2016, 2019, 2022, 2022 23H2 Edition, 2025
- Microsoft Office 2016, 2019, LTSC 2021, LTSC 2024, LTSC for Mac 2021, LTSC for Mac 2024
- Microsoft Office Deployment Tool
- Microsoft Excel 2016
- Microsoft Word 2016
- Microsoft 365 Apps for Enterprise
- Microsoft SharePoint Enterprise Server 2016
- Microsoft SharePoint Server 2019, Server Subscription Edition
- Microsoft SQL Server 2022, 2025
- Office Online Server
- Windows SDK
Impact:
Depending on the vulnerabilities exploited, a successful attack could lead to remote code execution, denial of service, elevation of privilege, information disclosure, security restriction bypass, spoofing or tampering on an affected system.
Recommendation:
Patches for affected products are available from the Windows Update / Microsoft Update Catalog. Users of affected systems should follow the recommendations provided by the product vendor and take immediate actions to mitigate the risk.
More Information:
- https://msrc.microsoft.com/update-guide/releaseNote/2026-Jan
- https://www.hkcert.org/security-bulletin/microsoft-monthly-security-update-january-2026
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-31096
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-55414
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-0386
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-20803 (to CVE-2026-20805)
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-20808 (to CVE-2026-20812)
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-20814 (to CVE-2026-20840)
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-20842 (to CVE-2026-20844)
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-20847 (to CVE-2026-20849)
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-20851 (to CVE-2026-20854)
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-20856 (to CVE-2026-20877)
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-20918 (to CVE-2026-20927)
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-20929
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-20931 (to CVE-2026-20932)
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-20934 (to CVE-2026-20941)
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-20943 (to CVE-2026-20944)
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-20946 (to CVE-2026-20953)
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-20955 (to CVE-2026-20959)
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-20962 (to CVE-2026-20963)
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-21219
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-21221
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-21265
