KB5122871: Overview with user sentiment and feedback

Overview

KB5122871 is a cumulative security update for Windows Server 2025 released on September 8, 2026 (OS Build 26100.33438). This patch includes the latest security fixes and quality improvements, incorporating non-security updates from the previous month's optional preview release. The update addresses multiple system components including certificates, networking, Remote Desktop services, and system monitoring capabilities.

General Purpose

• Certificate Authority Updates: Improves application compatibility during Windows certificate-authority transitions to newer signing certificates
• Network Failover Enhancement: Accelerates connection response times when network adapters disconnect, ensuring continued access to network storage and file services
• Remote Desktop Audio: Fixes audio redirection issues to ensure remote session audio plays correctly on local devices
• Sysmon Reliability: Prevents false security alerts for normal Session Manager activity, improves file monitoring stability, and enhances file archiving reliability
• Timezone Adjustment: Updates Morocco Standard Time to reflect the permanent UTC+00:00 transition effective September 20, 2026
• Servicing Stack Quality: Includes improvements to the Windows update installation component for more robust update delivery

General Sentiment

This update addresses important infrastructure and reliability concerns for Windows Server 2025 environments. While the patch delivers meaningful improvements across multiple critical systems, it carries documented known issues that warrant attention. The Remote Desktop Services instability reported by some organizations represents a significant concern, though Microsoft released a follow-up patch (KB5129235) on September 14, 2026 to resolve this issue. The WSUS error reporting limitation is a temporary security measure related to CVE-2025-59287.

Known Issues

• Remote Desktop Services Instability: RDS may become unstable after installation, causing RDP connection failures, sign-in issues, or servers hanging at "Please wait for the Remote Desktop Configuration"; related tools including MMC and File Explorer may become unresponsive; Windows Update page may display continuous loading indicator (resolved in KB5129235 released September 14, 2026)
• WSUS Error Reporting: Windows Server Update Services does not display synchronization error details after installing this update or later versions; this is a temporary limitation implemented to address CVE-2025-59287 Remote Code Execution vulnerability

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 2026-10-01 01:06 AM

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