The Node.js Permission Model is a process-level security feature that restricts what a Node.js application can do at runtime. Depending on how it is started, it can block access to files, child processes, network connections, or other sensitive resources unless the process has been explicitly granted permission.
This matters because Node.js apps often execute code that is partially trusted, such as plugins, scripts, or user-supplied logic. If an attacker finds a code execution bug, the permission model can reduce the blast radius by preventing the compromised process from reading secrets, spawning shells, or reaching internal services. It is not a full sandbox, but it is a useful defense-in-depth control that helps turn a logic flaw or injection into a much less dangerous incident.