It's not only Chrysler drivers that have to worry about hackers taking control of their cars from afar. UC San Diego researchers have found that you can control features on cars of many makes by exploiting vulnerabilities in cellular-capable dongles that are sometimes plugged into the vehicles' OBD-II ports, such as insurance trackers and driving efficiency tools. In the example you see above, the security team compromised a Corvette touting a Mobile Devices dongle (one of the most common varieties) through everyday text messages -- they could turn on the wipers or even cut the brakes. That same device is also set to allow remote tunneling using a universal 'private' key, making it easy for an intruder to get complete control over the adapter and its unfortunate host car.
You'll be glad to hear that Mobile Devices has already patched its hardware in response to the findings, and that the phone numbers for these dongles aren't normally public. You'd have to use brute force guesses to find a viable target. However, the concern is that other brands' dongles still have holes, and that many of these gadgets aren't getting updates in a timely fashion. It's feasible that an intruder could cause chaos by either forcing vulnerable cars off the road or making life miserable for their occupants.