I looked into the topic for you and here is what I found. I don't see why the cranberry fudge would be any different.

Frozen fudge will keep for months if wrapped in waxed paper then again in aluminum foil and stored in an air-tight container. Wrap each individual slice or the entire box with plastic or aluminium foil and seal thoroughly. Properly wrapped it should keep for several months. Leave fudge in its wrapping for at least two hours upon removal from the freezer to permit it to return to room temperature.

Fudge stored in the refrigerator can last 2-3 weeks when kept in an air-tight container.