We have a 2016.5 CX5 Touring with stock 17" rims. We happened to have a set of Security Chain Company SZ143 super Z6 tire chains for another car, and they say they fit the CX5 stock wheel/tire size. Before a trip to Utah this winter, we test-fit the chains on the front wheels. While they do "fit" the tires, on the back side of the tire the blue plastic-covered cable that holds the chains together rubs against a somewhat sharp piece of the strut. It doesn't rub much, and it's possible that the action of driving along with the tension from the rubber tensioner on the front of the wheel would make the chains clear the strut completely, I wasn't 100% convinced they would actually work. I did not test them with actual driving, we just moved the car a few inches in the driveway to confirm the contact between the chains and the strut.
At least in California we're covered for R1 and R2 with AWD and snow (M+S) tires, and I'm told by the time CHP goes to R3 (chains for everyone) they close the road anyway, but there is still a requirement that all drivers carry chains in winter regardless of their car's AWD capabilities. I'd hate to be stuck trying to get off a mountain and have my chains shredded after 100ft of driving (or worse yet getting caught up in the suspension). I'll be researching this some more before our next show/ice trip.