[justinclift]

Isn't it (exactly?) the same as finding a vulnerable JS library, and providing bad input to that?

That aside, if the C-to-wasm compiler were to add some of the safeguards mentioned it does sound like it'd go some way towards lessening the potential impact.

[rainforest]

Yes, if there was a library that eval'd unsanitised input the damage potential is the same.

The practical difference is that it's a lot harder to assure code written in unsafe languages is free of defects like this since they manifest as benign operations (every write to a buffer is a potential vector) rather than obviously dangerous operations. Concretely, you could grep for eval and convince yourself that each use is OK (assuming it's rare - it ought to be) but you couldn't do that for common language constructs that could be exploitable like writes to arrays/pointers.