Microsoft rolls out fixes for broken Windows VPN connections, but users report new network troubles

Microsoft has issued the KB5127646 and KB5127648 cumulative updates to resolve a persistent flaw disrupting Always On VPN connections across systems running Windows 11 24H2 and newer. The glitch, introduced during the September 2026 security updates, prevented machines from establishing automatic tunnels if an initial connection attempt failed. In such cases, connections would become trapped in a connecting state or trigger an error message stating that the specified port was already in use. [1][2]

For administrators who cannot deploy the latest patches immediately, Microsoft suggests modifying Always On VPN profiles to use a single dedicated protocol, either SSTP or IKEv2, instead of automatic protocol selection. The underlying Always On feature is designed to secure internet traffic automatically on Windows 10, Windows 11, and Windows Server devices by immediately connecting back to organizational networks. [1][2]

While some commercial users reported improved stability with third-party services like Surfshark after installing the October update, others report fresh problems. Multiple users on Microsoft Learn and social media say the patch breaks WPA2-Enterprise Wi-Fi authentication, disrupting 802.1X PEAP connections and preventing Windows 11 clients from reaching corporate networks across multiple hardware brands. [1]