InvalidInput

InvalidInput refers to data supplied to a program, system, or process that fails to meet required format, type, range, or business rules. It is a common classification for errors and exceptions encountered when input cannot be safely or meaningfully processed. The term is used both generically and as a name for specific error or exception types in various software libraries and frameworks.

Causes of invalid input include typographical mistakes, malformed data, missing required fields, corrupted transmissions, incorrect encoding, and attempts to supply values outside allowed ranges. Invalid input can be syntactic (violating format or schema), semantic (logically inconsistent with business rules), or contextual (appropriate in one context but invalid in another).

Consequences range from benign user-facing error messages to application crashes, data corruption, and security vulnerabilities such as injection attacks or buffer overflows when input handling is inadequate. Proper handling is therefore important not only for reliability and usability but also for safety and security.

Common mitigation strategies include explicit validation, input sanitization, type checking, use of schemas and validators, server-side checks even when client-side validation exists, clear error reporting, and least-privilege processing. Systems should log incidents without exposing sensitive internals and avoid failing open. Testing approaches such as fuzzing, boundary-value analysis, and unit tests help identify invalid-input handling issues. Designing clear user-facing constraints and feedback reduces the frequency of invalid input.