LibFuzzer

LibFuzzer Guide: In-Process Coverage-Guided Fuzzing for C and C++

LibFuzzer is LLVM's built-in coverage-guided fuzzer for C and C++. Unlike AFL++, which runs as a separate process, LibFuzzer runs inside your program's process — making it 10-20x faster. It's integrated directly into Clang, requires no external tools, and is used by

Fuzz Testing

libFuzzer with Clang: Writing Fuzz Targets, Sanitizers, and Corpus Management

libFuzzer is a coverage-guided fuzzing engine built directly into LLVM/Clang. Unlike AFL++, which runs as a separate process and instruments via compiler wrappers, libFuzzer runs the fuzz target as a library — making it significantly faster for library-level fuzzing. It's the engine behind Google's