> combination of said bad binary data and a poorly-written parser that didn't error out correctly upon reading invalid data

By now, if you write any parser that deals with any outside data and don't fuzz the heck out of it, you are willfully negligent. Fuzzers are pretty easy to use, automatic and would likely catch any such problem pretty soon. So, did they fuzz and got very very unlucky or do they just like to live dangerously?