KB5123065: Overview with user sentiment and feedback

Overview

KB5123065 is a September 2026 Monthly Rollup security update for Windows Server 2012, released on September 8, 2026. This cumulative update delivers security fixes and quality improvements as part of Microsoft's ongoing support for the operating system. The update is particularly significant as it addresses Secure Boot certificate deployment and other security vulnerabilities during a critical period when Secure Boot certificates began expiring in June 2026.

General Purpose

• Secure Boot Certificate Enhancement: Includes additional high-confidence device targeting data to expand coverage of devices eligible for automatic receipt of new Secure Boot certificates
• Security Vulnerability Fixes: Addresses multiple security vulnerabilities documented in the September 2026 Security Update Guide
• Quality Improvements: Cumulative fixes and quality enhancements as part of the standard monthly rollup process
• Certificate Deployment: Continues deployment of Secure Boot certificates via Windows updates to supported PCs and non-managed business devices

General Sentiment

This update addresses critical infrastructure concerns, particularly the Secure Boot certificate expiration issue affecting device boot capabilities. However, community reception has been tempered by a significant known issue affecting Remote Desktop Services stability. The update is necessary for security compliance, but administrators should exercise caution and have contingency plans in place before deployment, particularly in RDS-dependent environments.

Known Issues

• Remote Desktop Services might stop responding after September 2026 security update, causing RDP connection failures, sign-in issues, or servers hanging at "Please wait for the Remote Desktop Configuration"
• Related tools including Microsoft Management Console (MMC), RDS Licensing Diagnoser, and File Explorer might become unresponsive
• Windows Update page might stop responding and continuously display a loading indicator
• Installation may fail on Azure Arc-enabled devices running Windows Server 2012 if Subset of endpoints for ESU are not met

Disclaimer: We take measures to ensure that AI-generated content is of the highest possible quality, but we cannot guarantee its accuracy and recommend that users do their own independent research. Generated on 2026-09-14 12:55 AM

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