Sure, but you don’t need to prove that it’s false to claim defamation. As long as the defense is unable to prove that the accusation is definitively true, it could still be considered defamation. If he were to claim the report was false, then he’d have to provide evidence to that effect. By saying that it was defamatory, he only has to demonstrate that there is a lack of 100% certainty as to whether it is true or false, shifting the burden of proof onto CNN.
Source: my ass
It’s amazing how much my ass has taught me over the years.