[ElectroBuffoon]

For improved security with X11, try firejail+Xpra, or Qubes OS. They will not just help in the graphical front, but also others like processes and storage isolation.

[bitwize]

Workarounds for the inherently broken security model of X11.

Gee, if only there were a modern display server protocol with a fixed security model!

[jrm4]

All models are wrong, some are useful?

Theoretically, X11 is dangerous. But what isn't?