Yes they do, but mostly not strong, mature cats. Foxes have more sense than to tackle something that will surely mess them up, even if they finally kill it. Predators survive by picking off weaker prey, and staying healthy.
I read of a hungry fox that tackled a small dog, and was beaten off when the dog's pal, a siamese cat, joined in.
Have you ever seen the length of the fangs on a siamese cat?