Terminal2Shell is a design-level vulnerability in terminal emulators. When a terminal is launched, it immediately spawns a shell process and connects it directly to the user's keyboard. From there, the attacker can issue arbitrary commands with the full privileges of the logged-in user.
Researchers have confirmed that the shell will execute any command typed into it, including commands that delete files, install software, and modify system configuration. In some cases, the shell has been observed executing commands the user typed themselves.