Fuzz Testing
Fuzz testing is a security and robustness testing technique that supplies invalid, unexpected, or random inputs to software to identify crashes, vulnerabilities, and unexpected behavior.
“A test technique in which high volumes of meaningless data are used to generate test inputs.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Fuzz Testing?
Fuzz testing automatically generates unusual inputs to discover defects that traditional test cases may not expose.
Random input generation: Large numbers of unexpected inputs are tested automatically.
Robustness evaluation: Systems should handle invalid inputs safely.
Security value: Effective for finding crashes, buffer overflows, and input validation defects.
Real World Example
A regulated product team is preparing a release where Fuzz testing appears in reviews, test design conversations, or defect triage rather than as an isolated glossary word.
The risk is that the team treats Fuzz testing as interchangeable with nearby ISTQB terms. That makes test scope blurry and can lead to weak evidence for the release decision.
The tester anchors the discussion in the official definition, asks where the concept appears in the product, and designs examples that show the difference between Fuzz testing and similar ideas.
The page becomes useful in practice because Fuzz testing is connected to a specific testing decision, not memorized as a detached definition.
Practice Questions
Question 1
Which statement BEST describes Fuzz testing in the context of ISTQB terminology?
Question 2
A tester needs to explain Fuzz testing to a non‑technical stakeholder. Which approach is MOST appropriate?
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