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Microsoft: September updates cause RDS failures on Windows Server

Microsoft confirms September 2026 Patch Tuesday updates break Remote Desktop Services on Windows Server 2012+; Group Policy mitigations and rollback workarounds available.

Microsoft confirmed that September 2026 Patch Tuesday security updates cause Remote Desktop Services failures on Windows Server 2012 and later, plus Windows 10 and Windows 11. Symptoms include unstable RDS, RDP connection failures after several minutes, sign-in issues, servers hanging at 'Please wait for the Remote Desktop Configuration,' and unresponsive MMC, RDS Licensing Diagnoser, and File Explorer. Microsoft published per-version Group Policy mitigations (covering KBs such as KB5124008, KB5122880, KB5122878, KB5122871, KB5122882, KB5122876, KB5123099, KB5123065, KB5123066) and suggests restarting affected VMs. Rolling back the updates restores RDS functionality but removes this month's security fixes.

BleepingComputerupdated · 14h agofirst · 1d agoAdvisory 3 sources1

Windows Remote Desktop Client Vulnerability Allows Attackers to Execute Remote Code

Microsoft patched CVE-2026-69485, an 8.8 CVSS RCE flaw in the Windows Remote Desktop Client affecting Windows 10/11 and Server 2016-2025.

Microsoft's September 2026 updates fix CVE-2026-69485, an Important-rated remote code execution vulnerability (CVSS 3.1: 8.8, temporal 7.7) in the Windows Remote Desktop Client caused by use of an uninitialized resource. An authenticated attacker with low privileges could send a specially crafted network request to execute code on an affected server, with no user interaction required. Microsoft says the flaw was not publicly disclosed before patching and rates exploitation as 'Less Likely' with no evidence of active exploitation. Affected products span Windows Server 2016, 2019, 2022 and 2025 and Windows 10 (1607-22H2) and Windows 11 (23H2-26H1), with fixes delivered via KBs including KB5123099, KB5122876 and KB5122882.

Cyber Security Newsupdated · 6d agofirst · 6d agoVulnerability 3 sourcesCVE-2026-69485