Get Your Cat Care Questions Answered By Cat Vets ASAP
Anytime a cat has that high a temp, it warrants a trip to the vet. If you have a 24 hour facility, and the cost is not a big factor, I would recommend you take your cat in tonight. If this is not possible, I would be sure to have your pet see a vet first thing tomorrow.
A few of the possibilities (by no means the only causes of high fever in cats) can include Feline leukemia or an abscess. You'll want your vet to pinpoint the origin of the infection if possible and treat it quickly.
For now, keep the cat confined and offer water often. I would hold off on food for tonight.