I don't ever want to run untrusted code from the internet outside of a sandbox ever again. If WASI lives up to its full potential I won't have to - we'll have a robust, cross-platform sandboxing solution for running real applications.
WASM is great, but I think it's a wrong approach for sandboxing problem. It's technically possible to sandbox native applications (compiled into target machine code) using OS-builtin mechanisms, but it's not done for compatibility reasons, because this is the way things were done last 50 years or so.
You don't need to write platform-specific code if you use some cross-platform framework. For simple programs it may be enough to use only the standard library of your language of choice.
> single portable binary that can run on x86 windows, arm64 linux and in your browser with zero modification
It has little value. Compiling a separate binary for each OS isn't that hard, since only a handful of architectures and operating systems are actually in use. Using an abstract cross-platform binary (like WASM) in the other hand adds extra performance costs and other user-side overhead, which isn't strictly necessary.
That's a circular argument and "some" is doing a lot of work there. What cross-platform framework would you be referring to?
> It has little value. Compiling a separate binary for each OS isn't that hard, since only a handful of architectures and operating systems are actually in use. Using an abstract cross-platform binary (like WASM) in the other hand adds extra performance costs and other user-side overhead, which isn't strictly necessary.
It my have little value to you but that doesn't mean it has little value to everyone. I don't agree that compiling to multiple architectures is without difficulty and restricting yourself to only popular ones proves the point. What specific "other user-side overhead" would you be referring to? Lots of things aren't strictly necessary, that doesn't imply they're not necessary. Yes, there is a performance cost. Sometimes that cost is worth paying.
It is only now being inspected by researchers and attackers who have found sandbox escapes [0] (chrome 0day), out-of-bounds [1] / use-after-free [2] and many other [3] flaws [4] in WebAssembly which I also agree that it is not enough for sandboxing at all.
[0] https://nvd.nist.gov/vuln/detail/CVE-2026-11645
[1] https://bugzilla.mozilla.org/show_bug.cgi?id=2009901
[2] https://bugzilla.mozilla.org/show_bug.cgi?id=2013741
[3] https://www.miggo.io/vulnerability-database/cve/CVE-2026-269...
[4] https://github.com/bytecodealliance/wasm-micro-runtime/secur...
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[Re: 3] https://github.com/patriksimek/vm2
> vm2 attempts to sandbox untrusted JavaScript code within the same Node.js process as your application. It does this through a complex network of Proxies that intercept and mediate every interaction between the sandbox and the host environment.
> JavaScript is an extraordinarily dynamic language. Objects can be accessed through prototype chains, constructors can be reached via error objects, symbols provide protocol hooks, and async execution creates timing windows. The sheer number of ways to traverse from one object to another in JavaScript makes building an airtight in-process sandbox extremely difficult.
[Re: 4] https://github.com/search?q=repo%3Abytecodealliance%2Fwasm-m...
1) Replace webhooks in web apps with wasm binaries provided by the customer, but that run in the web app servers.
2) Safer plugin system for professional software (plugins for photoshop, plugins for IDEs, etc)
3) Safer mod system for games and server-side mods that run on the game-maker server.
Kind of strange that such experience still allows for WASM to be the target of C and C++ compilers, and there is no bounds checking support inside linear memory regions.
"The Java Virtual Machine is the cornerstone of the Java platform. It is the component of the technology responsible for its hardware- and operating system-independence, the small size of its compiled code, and its ability to protect users from malicious programs."
[1] https://docs.oracle.com/javase/specs/jvms/se26/html/jvms-1.h...
"The Java® programming language is a general-purpose, concurrent, object-oriented language."
Edit: Having thought a little, I appreciate that it's possible to compile for the JVM from source code which is not Java, which makes the JVM a compilation target. As far as I'm aware the JVM doesn't have first class support for this though, It's been tacked on as an afterthought. Compiling C to JVM bytecode for example doesn't appear to be an enjoyable process. WASM on the other hand was designed explicity to function as a compilation target for arbitrary languages.
Maybe I'm missing something, happy to be proven wrong.
WASI is a standard on where to poke holes on the sandbox for your specific use-case
WASM+WASI as a compilation target allows any program written for modern operating systems to work on any WASM runtime
For example a SaaS services that accepts WASM plugins could provide a WASI that lets the plugin write to a object-store filesystem (like AWS S3) provided by the SaaS owner.
For example here is Gzip in WASM: https://github.com/ColinTimBarndt/wasm-gzip
You will of course need to include a lot of support code to provide the relevant syscalls and otherwise emulate the environment that the code expects. But there are plenty of examples of that at this point.
tar -xf unzip.tar.gz && cd unzip
./configure CC=wasmcc
make
wasmruntime unzip.wasm testfile.zipWith WASM it may be the same, unless al major OS vendors integrate a WASM runtime so that it doesn't need to be installed separately.
I never used COM or CORBA, by the way, just too freaking ugly.
Maybe they should broaden their horizons.
https://en.wikipedia.org/wiki/List_of_Java_virtual_machines
And some like PTC or microEJ are missing from the list.
It doesn't have to, the program can bundle its own jre as its often the case, and then you also don't have to worry about jre compatibility. Downside is then you have many jres installed and of course you can't trust their sandboxing.
WASM doesn't remove version churn, the linked article literally discusses a newer version. Oh and the wonderful web compat story.
Also security, Java has reflection so you cannot reliably sandbox java libraries
Golem is a durable workflow platform and can run any wasm.
Point being you wouldn't run untrusted code in the first place and for "trusted code" you end up accepting it's access requirements anyway.
So logically I'd think that the malware would just get piggy bagged into actual non-obvious utility apps and nothing is gained.
Second problem is that the security model hoops make for terrible APIs and user experiences. Just look at the current filesystem browser APIs. It must be mentally challenging to design APIs to Be usable and the nerf them for security purposes to make them "not too usable".
Finally one must note that at least right now the webasm ecosystem is rather immature and the de-facto only tool (emscripten) is an amateur hour hobby project. So it's going to take some decades still before the tooling is really getting there.
But it doesn't need network access to be useful, so it doesn't have that permission and can't exfiltrate your data?
But specifically, this sandbox also kills all interop with your system, other apps/utilities, so way too disruptive for the purpose of isolating just from the network.
It should confine itself as the evolution from browser plugins.
As soon as you compile to WASM you no longer have the C FFI and the ability to call the OS systems interfaces for files, network and others.
It is extra work to move something to WASM vs just compiling it and running it in a sandbox.
Although... it doesn't say anything about releasing memory back to the host (I don't see a memory.shrink instruction) so maybe it's not all that helpful? Will WASM applications continue hogging the maximum amount of memory they've ever used until they're restarted?
A VM could release memory back to the host using memory ballooning, but this has to be managed manually somehow, at least with QEMU.