seL4

seL4 is a Microkernel that aims to improve speed and reliability, whilst having guaranteed behaviour with formal mathematical proofs. The CHERI fork of this adds RISC-V and Morello CHERI support to seL4. It utilizes the seL4 Microkit (a collection of abstractions for basic features) to provide a functional environment.

Project Home: https://github.com/CHERI-Alliance/CHERI-seL4

Downloads & Documentation

Fork VersionBased on Upstream VersionTargetDownloadDocumentation
HEAD (latest)
2025-12-31		v13.0.0-dev
2025-05-24		riscv64, morelloSource (seL4) Source (microkit)seL4 Exercises

Fork VersionBased on Upstream VersionTargetDownloadDocumentation
b3ed50e
2025-07-29		v13.0.0-dev
2025-05-24		riscv64, morelloSource (seL4) Source (Microkit)Release Notes
There are no pre-built binaries or versioned releases. Users must build from source using cheribuild

Project Status

Active development takes place in the CHERI-Alliance repository on the cheri-microkit branch. The CHERI-aware seL4 microkernel (CHERI-seL4) is currently not formally verified, and is experimental.

Technical discussion and design proposals for integrating CHERI into seL4: RFC-15: Support CHERI/Morello in seL4.

Building from Source

Please keep an eye out for our blog as we will soon share instructions for building from source.

Get Involved

Development for this project happens in the following places:

The active repository is CHERI-Alliance/CHERI-seL4 and CHERI-Alliance/CHERI-Microkit.

Builds are managed via the cheribuild tool. Dependencies include a specific CHERI-forked QEMU, LLVM, and GDB, as well as Rust for the Microkit.

Support is generally discussed in the CHERI CPU Slack in the #seL4 channel.

The CHERI Alliance seL4 working group hold meetings on the last Thursday of every month.

Vulnerability Disclosure

Please report security vulnerabilities relating to seL4 to heshamalmatary@capabilitieslimited.co.uk.

Something missing, incorrect?

This page was last updated on 20th January 2026. Please let us know of any corrections via support@thecapablehub.org, alternatively raise a GitHub pull request in our repo.