[toxik]

I mean, you’re not going to fuzz your way to bit twiddling together a small virtual computer inside of a compression stream.

[moyix]

Of course – but you can definitely fuzz your way to the initial vulnerability. The VM stuff is done once you have that vulnerability and are writing the actual exploit, which is a manual process.

[TechBro8615]

The blog says the PDF parsing was based on xpdf which is open source.