Windows 11 updates are breaking VPN access to WSL
Microsoft has issued a warning that updates to Windows 11 may have led to problems with networking via VPN in Windows Subsystem for Linux.
The problem sees the appearance of “No route to host” errors when using mirrored networking mode. Microsoft has not provided an exhaustive list of the third-party VPNs that are experiencing problems, but highlights Cisco Secure Client and OpenVPN.
Problems started with the KB5067036 update from October, but also exists in updates released after this. In an update to release notes, Microsoft warns of the known issue, saying that “Mirror networking on Windows Subsystem for Linux might fail”:
Symptoms
After installing the October 2025 Windows non-security update (KB5067036), released on October 28, 2025, or a later update, mirrored networking mode in Windows Subsystem for Linux (WSL) might cause issues with some third-party VPNs. When this issue occurs, you might see a “No route to host” error, even though the Windows host can still access the same destinations. As a result, you might be unable to access corporate resources over VPN and experience failures with VPN-dependent services.
This issue happens because the VPN application's virtual interface doesn’t respond to ARP (Address Resolution Protocol) requests. Reports indicate that Cisco Secure Client (formerly Cisco AnyConnect) and OpenVPN are affected.
Microsoft is trying to downplay the significance of the problem saying: “Home users of Windows Home or Pro editions are unlikely to experience this issue. It primarily affects connectivity to enterprise resources over VPN, including DirectAccess”.
While this is true to some extent, the word “primarily” is doing some heavy lifting in that last sentence. What it certainly does not mean is that the problem is exclusive to enterprise users, as there will undoubtedly be numerous home users who connect in precisely this way.
As is very common with problems that Microsoft acknowledges with its updates for Windows, there is no fix available yet. In this particular instance, there is not even a workaround available, with Microsoft issuing the standard statement that “the issue is under investigation, and additional information will be shared as soon as it becomes available”.
Have you been affected by this problem either as a home use or a business? What has the impact been for you and how have you been able to work around things with no fix being available? Share your experiences in the comments below.
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