Onstar can let cops disable your vehicle to stop a chase. If they can disable your vehicle, hackers can too.
If you have a fuse that controls the Onstar box you can pull the fuse, but you lose GPS maps and other accident reporting things. With the C8 Corvette it is buried into the engine controls and I have not seen a way to disable it. I cancelled my C8-Z06 order and I am trying to figure out if I can disable my Cadillac CT5 v Blackwing.