I couldn't find this information in the gentoo bugtracker, also 4.14.71/72 are not marked as stable yet, maybe I can provide some help getting this to stable.
So I figured I should maybe create a tracking bug. This is my first gentoo Bugreport, so please bear with me if I did anything wrong. Feel free to correct me!
I have currently a fresh build of 4.14.72 available and can test to some extend in virtual machines.
For a good write up about this imho quite serious priv esc bug see this blog entry:
maybe also relevant:
This is fixed in:
Can we stabilize the newer versions?