Coverage-guided fuzzing is a testing method that uses execution feedback to decide which inputs to generate next. As a program runs, the fuzzer tracks which branches, paths, or basic blocks were reached. Inputs that explore new code paths are kept and mutated further, while less useful ones are discarded. This makes it much more effective than blind random testing on complex software.
In cyber security, this matters because attackers often target parsers, file handlers, and protocol code where rare paths hide memory corruption, crashes, and logic bugs. Defenders use coverage-guided fuzzers to discover those flaws before they are weaponized, especially in native code such as C and C++ applications. In practice, it is a core technique behind automated vulnerability discovery, continuous testing pipelines, and crash triage workflows.