That's if they charge conspiracy in the first place.
The more general answer here is that the criminality of exploitation depends a lot on your state of mind (a property of law that something HN always has a hard time with). A professor teaching a class to an anonymous group of students is not at all the same thing, in criminal law, as that same professor standing behind foreign intelligence operatives coaching them on a targeted attack.
The confounder here is that there are statutes you can theoretically violate by providing some specific exploitation tools to foreign nationals.
The MIT professor, in an MIT classroom, is never going to be charged (same almost certainly goes for a consultant teaching an exploit class at Black Hat USA).
