Microsoft's Remote Desktop Services Plagued by Critical Bug
A critical bug in Microsoft's Remote Desktop Services (RDS) has caused widespread disruptions for administrators worldwide, following the September 2026 Patch Tuesday cumulative updates.
The issue affects session hosts running Windows Server 2019, 2022, and 2025, causing them to freeze hours after booting up. This results in RDP connections becoming stuck at 'Connecting...' and prevents logged-in users from disconnecting or logging off cleanly.
Affected hosts typically run normally for a few hours before symptoms emerge, often triggered by a single user session disconnecting or reconnecting. Independent kernel-level debugging by affected administrators points to a deadlock inside the RDP server base library, specifically in a routine called RDPSERVERBASE!WDLIB_Close.
The affected cumulative updates are not optional and have patched roughly 973 vulnerabilities across Microsoft's ecosystem, including critical Remote Desktop Services remote code execution flaws. Administrators who have removed the September update via DISM report immediate stabilization, while others have found partial relief by overriding feature flags or disabling WDDM/UDP-based Universal Rate Control Protocol.