David Justice

🎉 Introducing Wassette: a runtime for secure, sandboxed WebAssembly Component tool execution via the Model Context Protocol (MCP). Easily register reusable WASM tools inside AI agents like VS Code all without leaving the chat window. Start using it to safely extend your agent’s capabilities! 🚀

Our USENIX ;login; article on Crescendo just dropped! We discovered what might be the most powerful blackbox jailbreak technique - Crescendo is undefeated against all frontier AI models in every harm domain we tested. I'm presenting at USENIX Security on August 14th.
www.usenix.org/publications...

Refactor stub pthread library and enable unconditionally by whitequark · Pull Request #602 · WebAssembly/wasi-libc This PR changes the layout of the stub pthread library to match that of libc-top-half: splits it into (mostly) one file per function, and ensures the same API is exposed from both libraries, adding...

i've modified wasi-libc and wasi-sdk (PRs pending) so that you always have the concurrency APIs (pthread_*, thrd_*, <thread>, <mutex>, <atomic>) available to you, even in single-threaded targets. this makes porting applications (especially C++ ones) much, _much_ easier!

Hyperlight: Debugging hardware-protected guests - Microsoft Open Source Blog Find out how you can step through code in your guest micro-VM by attaching the GNU Debugger at runtime to debug Hyperlight guest micro-VMs.

For those who are about difficult hardware #virtualization efficiency and dev experience (WTF????) you might find @dblnz.dev's blog post on #hyperlight and interactive debugging interesting. It's a blast for any micro-guest, including #webassembly. opensource.microsoft.com/blog/2025/07...

WebAssembly, ‘Hyper VMs’ and Hypervisors: Fast Speeds, Intense Isolation In this article, we look at what happens when you combine WebAssembly with Hyperlight.

Missed this: very good article by @thenewstack.io on a @rejekts.io talk prior to #kubeconEU about #hyperlight and #webassembly in #envoy. Slow as a first draft; but getting faster and makes hostile multitenant #networkfunctions possible to imagine. thenewstack.io/webassembly-...

I confess to liking the progress made in the #Dual-LLM family of #llm security patterns started with @simonwillison.net's original Dual-LLM "separation of query concerns" in simonwillison.net/2023/Apr/25/....

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I put LLM spike coding into all my recruitment ads, in white font. Some of the replies are a lot of fun, and it sure speeds up shortlisting.

KubeCon + CloudNativeCon Europe 2025: Wasm I Right or Wasm I Wrong? a Review o... View more about this event at KubeCon + CloudNativeCon Europe 2025

Come join Taylor Thomas and I today as we discuss Wasm I Right or Wasm I Wrong? a Review of the Wasm Ecosystem at KubeCon + CloudNativeCon Europe 2025 sched.co/1tcxS #KubeCon

KubeCon + CloudNativeCon Europe 2025: Building WebAssembly Like It's 2011 - Da... View more about this event at KubeCon + CloudNativeCon Europe 2025

Come join Terence Lee and I today as we discuss Building WebAssembly Like It's 2011 - at KubeCon + CloudNativeCon Europe 2025 sched.co/1txGl

There's an incredibly talented and well liked PM I have the fortunate opportunity to observe and emulate.

Running #Wasm components inside of a hypervisor and being able to tailor the exact interface between the hosted application and the trusted compute base enables platform builders unequaled ability to tune precisely the access provided to untrusted application code.

Wasm-WG Meeting Notes §WASM WG | Meeting Notes 📆 📅 Fortnightly, Tuesdays at 5:00 pm CET/ 8:00 am PST Tockify Calendar Charter Join the Zoom Meeting Wasm Working Group Slack Past Meetings (TAG-Runtime channel) ...

Good day, folks! The #CNCF TAG-Runtime Wasm Working Group is meeting today in about 30 mins. We'll be covering updates on WASI cloud interfaces (blob, key/value, config, etc) and an update on WASI preview 3! Come join or just listen in! docs.google.com/document/d/1...

Build a Hyperlight C guest to safely execute javascript This video walks through the steps of running javascript inside hyperlight by building a c guest with quickjs. See https://aka.ms/hyperlight-quickjs for more info

There's a lot of words in the blog post 😅. If you have only a few minutes, you can see all the steps via vimeo.com/1063746996?s... (it's linked in repo with the code github.com/ludfjig/hype...).

Build a Hyperlight C guest to securely execute Javascript - Microsoft Open Source Blog This article will show you how to create a “guest” application that uses the Hyperlight library and have fun with some JavaScript. Learn more.

Delighted to see this post land! Learn how you can make a guest for Hyperlight to execute code in a secure sandbox with "Build a Hyperlight C guest to securely execute Javascript" opensource.microsoft.com/blog/2025/03...

If you were unable to make it to the Wasm working group with week, here's the recording youtu.be/dGvEMWYvenM?.... It was great to have the @zed.dev folks chat with us about their component model usage, and the JS/TS stack folks to discuss the tools and projects involved. Thank you, presenters!!

Wasm-WG Meeting Notes §WASM WG | Meeting Notes 📆 📅 Fortnightly, Tuesdays at 5:00 pm CET/ 8:00 am PST Tockify Calendar Charter Join the Zoom Meeting Wasm Working Group Slack Past Meetings (TAG-Runtime channel) ...

Hey Folks, the CNCF Wasm WG will be meeting today to talk about all things #Wasm. Joining us today are folks from @zed.dev to discuss their use of the component model to extend Zed. We'll also be joined by folks discussing their work on JS/TS WASI support. Join us: docs.google.com/document/d/1...

Please consider joining the community meetings if you run into any questions or if you want to bounce some idea around. We (Hyperlight project folks) would be delighted to help!

[Sandbox] Hyperlight · Issue #312 · cncf/sandbox Application contact emails David.justice@microsoft.com,Simon.Davies@microsoft.com,ralph.squillace@microsoft.com Project Summary Hyperlight is an open-source Rust library you can use to execute smal...

Very happy that the @cncf.io toc has voted to accept #hyperlight into the sandbox program! github.com/cncf/sandbox...

YouTube video by Rust Nation UK Microsoft is Getting Rusty: A Review of Successes and Challenges - Mark Russinovich

My closing keynote from Rust Nation UK last week is now online: "Microsoft is Getting Rusty: A Review of Successes and Challenges"

if Qb3, Nc7, Rd8#, right? So, either move for N ends with mate either by Q or R, I think.

qb3, ..., qg3#

WASM I/O • 27-28 Mar • Barcelona 2025 No More Printf: Interactive Debugging Wasm for web and server • Wasm I/O 2025. A 2-day WebAssembly conference in Barcelona, Spain

I'm super proud to be, with colleagues in humanity @anfibiacreativa.bsky.social ( @microsoft.com ) and @tschneidereit.bsky.social ( @fermyon.com ) to update our survey of debugging core #webassembly and #wasm components at #wasmio in Barcelona! 2025.wasm.io/sessions/no-...

It can now be done!

Here's @bluestein.bsky.social's uncensored thread of the town hall held by Rep. Rich McCormick (R-GA), in which an unhappy audience pushes back against DOGE cuts: threadreaderapp.com/thread/18927...

Wasm, Envoy, and Hyperlight Walk Into a Pod: No Vulnerabilities Allowed Cloud Native Rejekts Europe (London) 2025 Hyperlight, which has been submitted to CNCF, adds a new layer of security to WebAssembly workloads. By leveraging hardware-assisted virtualization via KVM or Hyper-V, Hyperlight creates ultra-lightwe...

At @rejekts.io there's tons of stuff to see. I'm looking forward to a little hot #envoy #webassembly network filter action with cfp.cloud-native.rejekts.io/cloud-native....

@markrussinovich.bsky.social takes the podium at @rustnationuk.bsky.social for @microsoft.com

teaser: there will be a #hyperlight mention. cool, cool...

Hyperlight: Achieving 0.0009-second micro-VM execution time - Microsoft Open Source Blog In this post, we’ll take the demo application and show how it demonstrates one way you can use Hyperlight in your applications. Learn more.

Learn how hyperlight can create virtualization-based sandboxes for WASM applications: