tree: 2548fccffdaa845e814dad5b7e247ad00a7c13d8 [path history] [tgz]
  1. .gitignore
  2. .gitmodules
  3. Android.bp
  7. Dockerfile
  11. Makefile
  12. NOTICE
  14. arch.h
  15. cmdline.c
  16. cmdline.h
  17. display.c
  18. display.h
  19. docs/
  20. examples/
  21. fuzz.c
  22. fuzz.h
  23. hfuzz_cc/
  24. honggfuzz.c
  25. honggfuzz.h
  26. includes/
  27. input.c
  28. input.h
  29. libcommon/
  30. libhfuzz/
  31. linux/
  32. mac/
  33. mangle.c
  34. mangle.h
  35. posix/
  36. report.c
  37. report.h
  38. sancov.c
  39. sancov.h
  40. sanitizers.c
  41. sanitizers.h
  42. subproc.c
  43. subproc.h
  44. third_party/
  45. tools/



A security oriented, feedback-driven, evolutionary, easy-to-use fuzzer with interesting analysis options. See USAGE for more data on the usage.

  • It's multi-threaded and multi-process: no need to run multiple copies of your fuzzer, as honggfuzz can unlock potential of all your available CPU cores. The file corpus is shared between threads (and fuzzed instances)
  • It's blazingly fast (esp. in the persistent fuzzing mode). A simple LLVMFuzzerTestOneInput function can be tested with up to 1mo iterations per second on a relatively modern CPU (e.g. i7-6700K)
  • Has a nice track record of uncovered security bugs: e.g. the only (to the date) vulnerability in OpenSSL with the critical score mark was discovered by honggfuzz. See the Throphies paragraph for the summary of findings to the date
  • Uses low-level interfaces to monitor processes (e.g. ptrace under Linux). As opposed to other fuzzers, it will discover and report hidden signals (caught and potentially hidden by signal handlers)
  • Easy-to-use, feed it a simple input corpus (can even consist of a single, 1-byte file) and it will work its way up expanding it utilizing feedback-based coverage metrics
  • Supports several (more than any other coverage-based feedback-driven fuzzer) hardware-based (CPU: branch/instruction counting, Intel BTS, Intel PT) and software-based feedback-driven fuzzing methods known from other fuzzers (libfuzzer, afl)
  • Works (at least) under GNU/Linux, FreeBSD, Mac OS X, Windows/CygWin and Android
  • Supports persistent fuzzing mode (long-lived process calling a fuzzed API repeatedly) with libhfuzz/libhfuzz.a. More on that can be found here
  • Can fuzz remote/standalone long-lasting processes (e.g. network servers like Apache's httpd and ISC's bind), though the persistent fuzzing mode is suggested instead: as it's faster and multiple instances of a service can be fuzzed at once in this mode
  • It comes with the examples directory, consisting of real world fuzz setups for widely-used software (e.g. Apache and OpenSSL)


  • Latest stable version: 1.2, but using the master branch is highly encouraged
  • Changelog


  • Linux - The BFD library (libbfd-dev) and libunwind (libunwind-dev/libunwind8-dev), clang-4.0 or higher for software-based coverage modes
  • FreeBSD - gmake, clang-3.6 or newer (clang-devel/4.0 suggested)
  • Android - Android SDK/NDK. Also see this detailed doc on how to build and run it
  • Windows - CygWin
  • Darwin/OS X - Xcode 10.8+
  • if Clang/LLVM is used to compile honggfuzz - link it with the BlocksRuntime Library (libblocksruntime-dev)


Honggfuzz has been used to find a few interesting security problems in major software packages; An incomplete list:

Projects utilizing Honggfuzz


The examples directory contains code demonstrating (among others) how to use honggfuzz to find bugs in the OpenSSL library and in the Apache HTTPD web server.


This is NOT an official Google product