Article
September 2026 Patch Tuesday: Key Vulnerabilities Overview
Introduction
Microsoft’s September security update addresses 974 vulnerabilities, including several critical issues. Many of these flaws, particularly those allowing remote code execution and affecting platforms like Windows and Azure, could be exploited by attackers to compromise your business. Importantly, some of these vulnerabilities are potentially exploitable over the internet, making 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 September 2026 Patch Tuesday
This month’s Patch Tuesday focuses on mitigating risks associated with serious vulnerabilities, especially in widely used platforms such as Windows, Azure, and Exchange Server. Notable vulnerabilities include issues that might allow attackers to execute code remotely or elevate their system privileges, potentially leading to unauthorized access to sensitive data. With some vulnerabilities already being exploited in the wild or affecting internet-exposed services, organizations need to prioritize these updates to protect their systems and data from possible breaches.
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 
September 2026 Patch Tuesday
Internal Network
Exposed to the Internet
Azure – Remote Code Execution Vulnerability
Azure, Microsoft’s cloud platform, is affected by a critical vulnerability allowing potential remote code execution. This could provide unauthorized control over cloud services.
Exchange Server – Remote Code Execution Vulnerability
The Microsoft Exchange Server is vulnerable to remote code execution when crafted emails are utilized. This could compromise the server’s integrity and security.
SQL Server – SQL Injection Vulnerability
A SQL injection vulnerability in Microsoft SQL Server allows unauthorized database access, which can lead to sensitive information exposure and unauthorized data manipulation.
SharePoint Server – Cross-site Scripting Vulnerability
Microsoft SharePoint Server contains a cross-site scripting vulnerability that could lead to user data being compromised if an attacker exploits it.
Windows – Remote Code Execution Vulnerability
Microsoft Windows is susceptible to remote code execution through malicious network packets, potentially allowing attackers to gain control of systems running Windows.
Internal Network
Windows Advanced Local Procedure Call (ALPC) – Elevation of Privilege Vulnerability
The Windows ALPC, which is a Microsoft Windows component managing inter-process communication, has an elevation of privilege vulnerability. This flaw allows attackers to gain elevated permissions, and there has been active exploitation in the wild.
Windows Update Stack – Elevation of Privilege Vulnerability
A vulnerability in the Windows Update Stack, responsible for managing updates for Microsoft products, can be exploited to elevate privileges. This flaw is being actively exploited.
Developer Tools – Arbitrary Script Execution Vulnerability
Microsoft’s developer tools are at risk of executing arbitrary scripts in developer environments, which could compromise code integrity and system security.
Office 2016 – Arbitrary Code Execution Vulnerability
In Microsoft Office 2016, opening malicious files can lead to arbitrary code execution, potentially compromising the user’s system and data.
Skype for Business – Denial of Service Vulnerability
A denial of service vulnerability in Skype for Business due to improper request handling could interrupt communication services, impacting business operations.
Conclusion
In conclusion, the September security updates from Microsoft include essential fixes for critical vulnerabilities that could greatly impact businesses. It is crucial to apply these updates as soon as possible to safeguard against potential attacks. Stay informed about security developments, ensure timely patching, and maintain a proactive stance in managing your organization’s IT infrastructure for continued protection.
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.