Path validation is the set of checks an application uses to make sure a file or folder path stays inside an approved directory boundary. It helps prevent path traversal, directory escape, and accidental access to sensitive locations such as private keys, configuration files, or another user’s data. Good validation usually normalizes the path, resolves relative segments like .., and checks the final resolved target before any read, write, or execute action occurs.
It matters in cyber security because many attacks abuse weak path handling to break out of a sandbox or reach secrets the app was never meant to touch. Defenders should validate on the server or trusted side, not just in the user interface, and they should compare canonical paths after resolving symlinks, mount points, and Unicode edge cases. When an AI tool, file manager, or backup agent can act on local files, strong path validation is one of the main barriers between normal workspace access and credential theft.