Microsoft fixes Always On VPN connection issues caused by September Windows updates
Summary
Microsoft’s KB5127648 and KB5127646 updates fix Always On VPN connection failures on affected Windows 11 systems. Until installing them, administrators can configure the VPN profile to use only SSTP or IKEv2.
Key points
- The issue affected up-to-date Windows 11 24H2 and later systems after installing September 2026 security updates.
- VPN connections using automatic protocol selection or fallback could stall at “Connecting” or fail after an initial connection attempt; later attempts could report that the port was already in use.
- Microsoft released KB5127648 and KB5127646 on October 14 to resolve the issue.
- As a temporary workaround, administrators can configure Always On VPN to use only SSTP or only IKEv2, according to their environment.
Article Details
- Event Type
- Microsoft released updates fixing Always On VPN connection failures caused by September 2026 Windows security updates.
- Impact
- Affected Always On VPN connections on Windows 11 24H2 and later could remain stuck in a Connecting state or fail after an initial connection attempt failed; some subsequent attempts showed “The specified port is already in use.” Microsoft released KB5127648 and KB5127646 to address the issue. Until installing the October 2026 update, organizations could mitigate it by configuring the VPN profile to use SSTP only or IKEv2 only.
Vendors
Products
Always On VPNMicrosoft has resolved a known issue that caused Always On VPN connection issues after installing the September 2026 Windows 11 security updates.Windows 11Microsoft has resolved a known issue that caused Always On VPN connection issues after installing the September 2026 Windows 11 security updates.