Article
January 2026 Patch Tuesday: Key Vulnerabilities Overview
Introduction
Microsoft’s January security update addresses 114 vulnerabilities, including several critical issues. Many of these flaws, particularly those allowing remote code execution and affecting widely used platforms like Microsoft Office and Windows components, could be exploited by attackers to compromise your business. Importantly, while no specific vulnerabilities are categorized as exposed to the internet this month, the severity of flaws within the internal network makes prompt updates essential. In this article, we provide an overview of this month’s patches and highlight the most notable security issues that require immediate attention.
Summary of January 2026 Patch Tuesday
This month’s Patch Tuesday is a significant one, as it fixes 114 different issues. Some of these problems are considered ‘critical’, meaning they need immediate attention. The updates address various vulnerabilities that hackers could exploit to gain unauthorized access to systems or cause harm. Notable fixes include those for Microsoft Office and Windows components, which are widely used globally. By applying these updates, users can protect their systems from potential threats and ensure they continue to operate reliably.
Understanding these updates is crucial in protecting enterprise environments. Below, we categorize the vulnerabilities based on their exposure to the internet.
Updates are listed according to their CVSS Score
Exposed to internet 
January 2026 Patch Tuesday
Internal Network
Exposed to the Internet
Nothing this month.
Internal Network
Microsoft Office – Remote Code Execution
Microsoft Office, a suite including applications like Word, Excel, and PowerPoint, has a critical remote code execution vulnerability. This flaw enables attackers to execute code without user interaction, which could lead to unauthorized access and control over affected systems.
Microsoft Office – Remote Code Execution
A critical remote code execution vulnerability is present in Microsoft Office, resulting from use-after-free conditions in its components. This vulnerability allows attackers to run arbitrary code, posing significant security risks.
Microsoft Excel – Remote Code Execution
Microsoft Excel, part of the Microsoft Office suite, has a critical remote code execution vulnerability due to an untrusted pointer dereference. This flaw can be exploited by attackers to execute arbitrary code upon file interaction, threatening system integrity.
Microsoft Excel – Integer Underflow
An integer underflow vulnerability in Microsoft Excel, a component of the Microsoft Office suite, allows remote code execution when a malicious file is opened. This issue could be leveraged by attackers to gain unauthorized control over affected systems.
Agere Soft Modem Driver – Elevation of Privilege
The Agere Soft Modem Driver, a third-party software component supporting modem hardware on Windows systems, has an elevation of privilege vulnerability. Attackers can exploit this flaw to escalate privileges to SYSTEM-level, gaining nearly full control over affected systems.
Windows Graphics Component – Elevation of Privilege
A critical elevation of privilege vulnerability exists in the Windows Graphics Component due to a use-after-free flaw. This component handles rendering and display of graphics within the Windows OS, and exploitation of this vulnerability could allow attackers to execute code with elevated privileges.
Windows Local Security Authority Subsystem Service (LSASS) – Remote Code Execution
LSASS, a core Windows process managing security policies and user authentication, suffers from a critical remote code execution vulnerability. A use-after-free condition allows attackers to execute arbitrary code, potentially compromising system security.
Windows Virtualization-Based Security (VBS) Enclave – Privilege Elevation
Windows VBS Enclave, enhancing data protection and system integrity, is affected by a heap-based buffer overflow that can lead to privilege elevation and potential security bypass. Exploitation may allow attackers to elevate privileges, undermining system security.
Windows Secure Boot – Security Feature Bypass
Windows Secure Boot, a security standard ensuring a computer boots only using trusted software, is vulnerable to a security feature bypass. This vulnerability allows attackers to exploit weaknesses in certificate updates, potentially leading to unauthorized system modifications or access.
Desktop Window Manager – Information Disclosure
Windows Desktop Window Manager, responsible for rendering the graphical user interface of the Windows operating system, is affected by an information disclosure vulnerability. This issue allows local attackers to access sensitive system memory addresses, potentially leading to unauthorized access to critical information.
Conclusion
The key takeaway from this month’s Patch Tuesday is the importance of keeping your software up to date. By installing the latest updates from Microsoft, you close doors that hackers could use to breach your systems. It’s a simple yet effective way to protect your digital life. Always make sure to back up your data, and be cautious with emails and links from unknown sources. Staying informed and proactive is your best defense against cyber threats.
Have questions about implementing these patches or securing your IT environment? Schedule a call with At-Bay’s Advisory Services team to get started.
About CVSS
The Common Vulnerability Scoring System (CVSS) is an industry-standard framework for evaluating and communicating the severity of software vulnerabilities. It provides a numerical score that helps organizations prioritize and address security issues effectively. CVSS scores quantify the severity of a vulnerability on a scale from 0 (no severity) to 10 (critical severity). CVSS considers multiple factors, including; Exploitability, Impact, Exploit code maturity, Remediation level, Report confidence. The system enables organizations to compare and prioritize vulnerabilities based on their potential impact on IT infrastructure.
References
- https://blog.qualys.com/vulnerabilities-threat-research/2026/01/13/microsoft-patch-tuesday-january-2026-security-update-review
- https://blog.talosintelligence.com/microsoft-patch-tuesday-january-2026/
- https://www.crowdstrike.com/en-us/blog/patch-tuesday-analysis-january-2026/
- https://www.rapid7.com/blog/post/em-patch-tuesday-january-2026/
- https://www.bleepingcomputer.com/news/microsoft/microsoft-january-2026-patch-tuesday-fixes-3-zero-days-114-flaws/
- https://www.computerweekly.com/news/366637296/microsoft-patches-112-cves-on-first-patch-tuesday-of-2026
- https://krebsonsecurity.com/tag/microsoft-patch-tuesday-january-2026/
- https://msrc.microsoft.com/update-guide/releasenote/2026-jan