Earlier quoted context omitted.
Those aren't inherently insecurities, but the way X implemented them was quite insecure. Wayland is now having to do the heavy lifting of defining a secure protocol to implement it and migrating the entire Linux GUI ecosystem to using the new mechanisms. Also, I can take screenshots just fine on Wayland via KWin. I can't pick arbitrary 3p apps just yet but KWin's screenshotter is fine. Not sure about screen recording…
"secure" really has become a buzzword. > Those aren't inherently insecurities, but the way X implemented them was quite insecure. In what way does X.org add any security holes to the average Linux desktop where you have programs (from a trusted package repository) which can access everything your user account can?
These are very old issues and are some of the major reasons Wayland was started in the first place. May want to read up on what the problems identified by the project were when it started considering all X maintainers migrated their time and energy to Wayland.