As soon as things get smart, something stupid also happens: they become vulnerable to attack. This was the case (though over-hyped, perhaps) of printers that cybersecurity researchers warned could be hijacked and theoretically set on fire. And now, argues Willie D. Jones of IEEE Spectrum, it could be the fate of our latest smart devices: our cars.

Cars are dangerous enough, without the problem of a cyberattack thrown in the mix. But unfortunately, researchers are coming up with several ways cars could be vulnerable to hackers. Wi-Fi, cellular, and Bluetooth connections exist in cars to help us communicate or be entertained as we drive, but a few research groups have already shown how these channels can be hijacked by someone with malicious intent.

One research team at UC San Diego and University of Washington demonstrated it was possible to do an absurd attack that could allow criminals to locate cars’ GPS coordinates, override their security systems, unlock their doors, and start their engines–in other words, a carjacker’s dream come true. A even worse scenario envisioned by one researcher: a hack that would disable your breaks while you’re driving on the highway.

All this doesn’t merely exist in the academic journals of a few university white-hat hackers. Some of this stuff has already happened. Jones points to a September report from McAfee that spoke of an instance where a disgruntled employee at a Texas car dealership was able to shut off the engines of 100 cars at once. A recent blog post from McAfee goes into detail on several other hacks, most of them white-hat, that would seem like the purview of science fiction, were it not for the fact that they’re real. Fiction has already been made fact, per McAfee: “In the movie ‘Live Free or Die Hard,’ actor Justin Long portrays a computer hacker who social-engineers the call center agent into remotely starting the car. That was Hollywood; yet at the recent Black Hat USA conference, security researchers Don Bailey and Mat Solnik expanded on earlier research to locate and attack car telematics systems.”

As in so many things, if Hollywood has imagined it, some clever hacker is already probably making it happen. Says McAfee’s Jimmy Shah: “As devices get smarter and more connected, we’re going to see more attacks targeted at them.” Let’s just hope we get smarter, too–smart enough to guard against these attacks before they happen.