Not listed on the website for some reason.
All versions of the Samba file server prior to 4.15.0 are affected by
CVE-2021-20316. There will be no patches available for older Samba
versions before 4.15 and 4.15 itself is already secure.
* CVE-2021-20316: Symlink race error can allow metadata read
and modify outside of the exported share.
Please update affected systems as soon as possible.
Earlier versions *are* affected but as explained in the advisory, can't be trivially fixed. So, probably time to stable a 4.15.x (bug 828680).
So, all we need to do is stable 4.15.x.