Shanthem Rights

Hypothetically, who has the rights to the Shanthem as a piece of music? The music department got it from Shan. Is it CBS' or hers? If someone claimed it was stolen from them, who would they sue? They'd be accusing Shan of lying, but CBS aired her humming it. If someone else used it in their media, who would sue?

Not scheming anything, just pondering Survivor's big questions during the off-season.