CBS does seem like the by far the most likely channel to air it, at that ('cause rights and such).
Unless something truly monumental happens to change what CBS is and the audience they are chasing, and I'm sure there will be plenty of advance notice of something like that, there is no possibility at all that CBS will show Star Trek. I doubt they'd ever show sci if of any kind, unless it's the barely sci if type of show like Person of Interest.
CBS Studios may produce Star Trek, but it will be shown elsewhere, where it makes more sense.
The way network ratings are going, I wonder how long broadcast of any kind will exist.