xdg-desktop-portal-hyprland (aka an XDG Desktop Portal backend for Hyprland) before 1.3.3 allows OS command execution, e.g., because single quotes are not used when sending a list of app IDs and titles via the environment.
https://github.com/hyprwm/xdg-desktop-portal-hyprland/releases/tag/v1.3.3
https://github.com/hyprwm/xdg-desktop-portal-hyprland/issues/242