VPN Connectivity Issues After Installing Windows 11 Update KB5055523 (OS Build 26100.3624)

Question

I’m currently using Windows 11 Enterprise, version 24H2, with OS build 26100.3624 and Windows Feature Experience Pack 1000.26100.66.0.

On April 10, 2025, the cumulative update KB5055523 (Security Update for Microsoft Windows) was installed automatically via Windows Update.

After the installation, I attempted to connect to our corporate networks using Cisco VPN and FortiClient VPN, as I do daily. Both VPN clients successfully established connections. However, I was unable to access any internal servers, applications, or URLs that are normally accessible once connected.

I contacted the respective network teams managing the environments behind these VPNs, and they confirmed that there were no issues or changes on their side.

As a troubleshooting step, I uninstalled the KB5055523 update and rebooted the system. After this rollback, all VPN-related network access returned to normal and functioned as expected.

This strongly suggests that the KB5055523 update may be introducing changes that interfere with VPN traffic routing or firewall behavior.

I would appreciate it if this could be looked into, as it may potentially impact many enterprise users relying on VPN connectivity after this update.

Answer 1

Same problem here. Verified on two different computers. One brand new out of the box, one a few years old. After installing KB5055523 via windows update, VPN no longer works.