Looking forward to a future where we can arbitrarily DoS anyone with a PDF that computes massive swaths of prime numbers.
PDFs can already do arbitrary computation. You can even play tetris in them.
Can't that future adopt basic resource / complexity limits to defuse the DOS bomb?
You used to be able to DoS the user's browser by sticking thousands of tiny animated gifs on the same page. You can't do that any more (AFAIK) because that's a bug so the browser developers fixed it. This is the same thing.
It's odd that apple didn't proactively guard against such concerns when adding a new format.