Microsoft has acknowledged that recent security updates for Windows 11 are causing networking complications for enterprise users utilizing the Windows Subsystem for Linux (WSL), particularly affecting those who installed the KB5067036 update from October 28, 2025, or subsequent updates like KB5072033. Users are experiencing difficulties with certain third-party VPN applications when the mirrored mode networking feature is enabled, leading to "No route to host" errors within WSL environments. This issue primarily impacts OpenVPN and Cisco Secure Client. The root cause is the failure of VPN applications' virtual network interfaces to respond to Address Resolution Protocol (ARP) requests. Home users on Windows Home or Pro editions are unlikely to be affected. Microsoft is investigating the issue but has not provided a timeline for a resolution or workarounds. WSL, launched in March 2018, allows users to run Linux distributions natively on Windows, with WSL 2 introduced in May 2019 featuring a real Linux kernel. Microsoft open-sourced WSL at Microsoft Build 2025, making its source code available on GitHub, except for some components that remain part of Windows.