Overview

On January 14, NSFOCUS CERT detected that Microsoft released the January Security Update patch, which fixed 112 security issues involving widely used products such as Windows, Microsoft Office, Microsoft SQL Server, Azure, etc., including high-risk vulnerability types such as privilege escalation and remote code execution.

Among the vulnerabilities fixed by Microsoft’s monthly update this month, there are 8 critical vulnerabilities and 104 important vulnerabilities. These include 1 vulnerability that has been detected for wild exploitation:Desktop Window Manager Information Disclosure Vulnerability (CVE-2026-20805)Please update the patch as soon as possible for protection. For a complete list of vulnerabilities, please refer to the appendix.

Reference link: https://msrc.microsoft.com/update-guide/releaseNote/2026-Jan

Key Vulnerabilities

Based on the product popularity and vulnerability importance, this update contains vulnerabilities with greater impact. Relevant users are requested to pay special attention:

Desktop Window Manager Information Disclosure Vulnerability (CVE-2026-20805):

An information disclosure vulnerability exists in Desktop Window Manager (DWM). Since DWM fails to properly protect memory information when processing operations related to remote ALPC ports, an authenticated attacker can obtain sensitive information of the system through specially crafted requests. This vulnerability has been exploited in the wild, with a CVSS score of 5.5.

Official announcement link:

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20805

Microsoft Office Remote Code Execution Vulnerability (CVE-2026-20952/CVE-2026-20953):

A remote code execution vulnerability exists in Microsoft Office. Due to the use-after-free problem of Microsoft Office when processing specially crafted documents, an unauthenticated attacker can send an email containing a malicious link to the user, which will cause remote code execution after the user previews or clicks it. CVSS score is 8.4.

Official announcement link:

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20952

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20953

Microsoft Excel Remote Code Execution Vulnerability (CVE-2026-20955/CVE-2026-20957):

A remote code execution vulnerability exists in Microsoft Excel. Due to the untrusted pointer dereference and integer underflow problems of Excel, an unauthenticated attacker can trick a user into opening a malicious file, thereby executing arbitrary code on the victim’s host. CVSS score is 7.8.

Official announcement link:

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20955

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20957

Microsoft Word Remote Code Execution Vulnerability (CVE-2026-20944):

A remote code execution vulnerability exists in Microsoft Word. Due to the out-of-bounds read problem of Word, an unauthenticated attacker can trick a user into opening or previewing a pane by making a malicious file, thereby executing arbitrary code in the user’s context. CVSS score is 8.4.

Official announcement link:

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20944

Windows Local Security Authority Subsystem Service (LSASS) Remote Code Execution Vulnerability (CVE-2026-20854):

A remote code execution vulnerability exists in Windows LSASS. Due to the use-after-free issue of Windows LSASS, an authenticated attacker can modify specific directory attributes and provide specially crafted data, causing the system to reference invalid memory to execute arbitrary code. CVSS score is 7.5.

Official announcement link:

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20854

Windows NTFS Remote Code Execution Vulnerability (CVE-2026-20840):

A remote code execution vulnerability exists in Windows NTFS, which could allow an authenticated attacker to execute arbitrary code locally due to a heap-based buffer overflow in Windows NTFS. CVSS score is 7.8.

Official announcement link:

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20840

Windows Graphics Component Privilege Escalation Vulnerability (CVE-2026-20822):

A privilege escalation vulnerability exists in the Windows Graphics Component, which allows an authenticated local attacker to elevate privileges to SYSTEM through conditional competition release reuse (use-after-free). CVSS score is 7.8.

Official announcement link:

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20822

Windows Virtualization-Based Security (VBS) Enclave Privilege Escalation Vulnerability (CVE-2026-20876):

There is a privilege escalation vulnerability in Windows VBS. Due to the heap-based buffer overflow problem of VBS Enclave, an authenticated local attacker can elevate privileges to SYSTEM. CVSS score is 6.7.

Official announcement link:

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20876

Scope of Impact

The following are the affected product versions of some key vulnerabilities. For the scope of products affected by other vulnerabilities, please refer to the official announcement link.

Mitigation

Patch update

At present, Microsoft has officially released security patches to fix the above vulnerabilities for supported product versions. It is strongly recommended that affected users install patches as soon as possible for protection. The official download link:

https://msrc.microsoft.com/update-guide/releaseNote/2026-Jan

Note: Patch updates for Windows Update may fail due to network problems, computer environment problems, etc. After installing the patch, users should check whether the patch has been successfully updated in time.

Right-click the Windows icon, select “Settings (N)”, select “Update and Security”-“Windows Update”, view the prompt information on this page, or click “View Update History” to view the historical update status.

For updates that have not been successfully installed, you can click the update name to jump to the Microsoft official download page. It is recommended that users click the link on this page and go to the “Microsoft Update Catalog” website to download the independent program package and install it.

Appendix

Statement

This advisory is only used to describe a potential risk. NSFOCUS does not provide any commitment or promise on this advisory. NSFOCUS and the author will not bear any liability for any direct and/or indirect consequences and losses caused by transmitting and/or using this advisory. NSFOCUS reserves all the rights to modify and interpret this advisory. Please include this statement paragraph when reproducing or transferring this advisory. Do not modify this advisory, add/delete any information to/from it, or use this advisory for commercial purposes without permission from NSFOCUS.

About NSFOCUS

NSFOCUS, a pioneering leader in cybersecurity, is dedicated to safeguarding telecommunications, Internet service providers, hosting providers, and enterprises from sophisticated cyberattacks.

Founded in 2000, NSFOCUS operates globally with over 4000 employees at two headquarters in Beijing, China, and Santa Clara, CA, USA, and over 50 offices worldwide. It has a proven track record of protecting over 25% of the Fortune Global 500 companies, including four of the five largest banks and six of the world’s top ten telecommunications companies.

Leveraging technical prowess and innovation, NSFOCUS delivers a comprehensive suite of security solutions, including the Intelligent Security Operations Platform (ISOP) for modern SOC, DDoS Protection, Continuous Threat Exposure Management (CTEM) Service and Web Application and API Protection (WAAP). All the solutions and services are augmented by the Security Large Language Model (SecLLM), ML, patented algorithms and other cutting-edge research achievements developed by NSFOCUS.

The post Microsoft’s January Security Update of High-Risk Vulnerability Notice for Multiple Products appeared first on NSFOCUS, Inc., a global network and cyber security leader, protects enterprises and carriers from advanced cyber attacks..

*** This is a Security Bloggers Network syndicated blog from NSFOCUS, Inc., a global network and cyber security leader, protects enterprises and carriers from advanced cyber attacks. authored by NSFOCUS. Read the original post at: https://nsfocusglobal.com/microsofts-january-security-update-of-high-risk-vulnerability-notice-for-multiple-products/