Why would CBS be approached about this? Unless I missed something, Star Trek V belongs to Paramount. CBS only owns the TV material.
Well, that's a little iffy. Paramount has rights to the Trek films, but CBS owns the entire franchise. The name Star Trek
and related indicia are trademarks of CBS which Paramount is licensed to use in their movies, though Paramount is the copyright holder for the movies (but CBS has a joint copyright with Paramount on the novelizations, comics, etc.). And since characters like Kirk, Spock, McCoy, etc. were created for a TV series that CBS owns, that probably means that Paramount is only permitted to use them under license from CBS.
So even though ST V is a production of/copyrighted by Paramount, if anyone wanted to release a new DVD with Star Trek
in the title, even a re-edit of an old movie, they'd at the very least need CBS's permission to use the trademark.