Microsofts WSL 2.6.0 Update: A Leap Towards Open Source for Linux on Windows

Microsoft has released an update to the Windows Subsystem for Linux (WSL) toolset, version 2.6.0, which enables the execution of Linux applications on Windows. This update is notable as it marks the first release following the open-sourcing of command-line utilities, background processes for Linux environments, and services used to run virtual machines under the MIT license. Prior to this, only the components of WSL related to the Linux kernel and the graphical stack known as wslg had their source code made available, while all other related tools remained proprietary.

The modifications and enhancements introduced in WSL version 2.6.0 largely focus on bug fixes and improving overall stability.

WSL provides a virtual machine equipped with a full Linux kernel (based on version 6.6), allowing various Linux distributions to run. This kernel incorporates WSL-specific adjustments, including optimizations for faster startup times and reduced memory usage, the ability to return memory freed by Linux processes back to Windows, and configurations to eliminate unnecessary drivers and subsystems. It is installed within a separate virtual hard disk (VHD) with an ext4 file system and a virtual network adapter.

The Windows for Linux version 2.0.0 was released in September 2024.

In May 2025, Microsoft opened the source code of the Windows Subsystem for Linux under the MIT license, encompassing command-line tools (wsl.exe and wslg.exe), background services (wslservice.exe), and Linux-side daemons responsible for network operations, launching other daemons, and managing port forwarding. This allows third-party developers to download the WSL code and compile it from source, facilitating bug fixes or new feature additions. The only components that remain proprietary and are not part of the open-source WSL are Lxcore.sys, the kernel driver for WSL 1, and P9rdr.sys and p9np.dll, which are utilized for file system redirection via «\\wsl.localhost».