What does fuzzing mean?
Fuzzing is an automated software testing technique in which a program is bombarded with vast quantities of random, malformed, or otherwise unexpected input to see how it responds. If the software crashes, hangs, or misbehaves, the fuzzer has likely exposed a bug — sometimes a serious security vulnerability. The term also survives in a much older, informal sense describing the act of covering something with fine, fuzzy fibers. In computing, fuzzing ranges from simple mutation of existing files (mutation-based fuzzing) to sophisticated coverage-guided methods that track which code paths have been reached and steer future tests toward new ones. Since Barton Miller's pioneering experiments at the University of Wisconsin–Madison in 1990 showed that random data could crash nearly every Unix utility tested, fuzzing has become a mainstay of security research and quality assurance. Today it runs continuously over major codebases through platforms such as Google's OSS-Fuzz, quietly uncovering flaws before attackers can exploit them.
An automated software testing technique that supplies random, malformed, or unexpected input to a program in order to reveal bugs, crashes, or security vulnerabilities.
"Continuous fuzzing of the parser caught a memory-corruption bug before release."
Often used attributively alongside terms like 'mutation-based' or 'coverage-guided'.
The act of making something fuzzy or covering it with fine, fibrous material (informal).
"He was fuzzing the felt with a wire brush to create texture."
Older, non-technical sense; uncommon today outside craft contexts.
Fuzzing was born from chaos: in 1990, Barton Miller's team randomly pounded Unix programs with garbage data — and nearly every single one crashed.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of fuzzing
The word 'fuzzing' derives from 'fuzz', a term of uncertain origin used since roughly the seventeenth century to describe loose, fibrous matter such as fluff on cloth. The computing sense emerged around 1988–1990, when Barton Miller and colleagues at the University of Wisconsin–Madison coined the name for their technique of flooding Unix programs with random input, borrowing the older sense of chaotic, unruly material. Related forms include the noun 'fuzz' (both fiber and, informally, the police), the adjective 'fuzzy', and the agent noun 'fuzzer'.
Related word forms
How fuzzing is actually used
In modern usage, 'fuzzing' overwhelmingly refers to the software security technique; the fiber-related sense is rare and mostly informal.
Easily confused with fuzzing
'Buzzing' refers to a low humming sound, whereas 'fuzzing' refers either to automated software testing or to covering something with fine light fibers.