Ok, looking at it a bit more seriously - I needed something a bit closer to my level to understand, especially how it relates to grub.
https://www.theregister.com/2020/07/29/grub2_code_exec_flaw/To me, is sure looks like promoting
ISO BOOTING would help prevent that overflow trigger targeting grub.cfg on the next reboot!
I do that already on some of my projects, picking up embedded extensions from another iso, or use custom setups simply starting persistence elsewhere with tce-setdrive, tce= directives etc etc. But many of my TC sticks are ISO BOOT already, not on writable filesystems. Just my choice.
However, as noted, by the time one gets to this point security wise, you've already lost the keys to the kingdom. This just piles-on.
And, even though I favor iso-boot, if anyone thought of running TinyCore in an enterprise environment should be immediately fired. Home use, ok.