The way we try to address security issues is get Unraid releases out in a timely manner. Unfortunately, that hasn't been happening quickly enough lately. It is being delt with behind the scenes and discusssed internally. It's much better all around to release a new version of Unraid with all the latest security fixes, rather than going back and applying patches. Unraid was not designed to apply patches.
For the moment there are several ways to alleviate your comcerns:
Disable mac OS interoperability.
Upgrade to one of the 6.10 rc's. They are using a later version of samba. I'm working with the beta rc3 and the samba is at version 4.15.3.