A file-read vulnerability is a flaw that lets an attacker retrieve files from a server that were not meant to be exposed. The leaked content may include source code, configuration files, environment variables, log files, or credentials. In many cases, the bug appears when an application mishandles paths, request parameters, or access checks and ends up reading local files on behalf of the attacker.
This matters because file reads often reveal the secrets that protect the rest of the system. Even if the initial flaw does not allow code execution, exposed tokens or internal paths can help an attacker move deeper into an environment. Defenders look for suspicious requests with unusual file paths, directory traversal patterns, or repeated access to API endpoints that should never return raw files. Fast patching, log review, and secret rotation are common responses when a file-read issue is discovered.