WASM is interesting in that its memory design prevents reading anything outside the memory allocated for the vm. To this point, I don't think you would get much use from using this within WASM.

That's not to say, of course, that WASM VMs don't employ various security measures. V8, at least, uses (mostly) the same optimization pipeline for WASM that it does for JS, so all the years of security that have gone into JS are gained by WASM for free.