September 24, 2019

197 words 1 min read



Scalable fuzzing infrastructure.

repo name google/clusterfuzz
repo link
language Python
size (curr.) 56274 kB
stars (curr.) 4144
created 2019-01-29
license Apache License 2.0


ClusterFuzz is a scalable fuzzing infrastructure that finds security and stability issues in software.

Google uses ClusterFuzz to fuzz the Chrome Browser and as the fuzzing backend for OSS-Fuzz.

ClusterFuzz provides many features which help seamlessly integrate fuzzing into a software project’s development process:

  • Highly scalable. Google’s internal instance runs on over 25,000 machines.
  • Accurate deduplication of crashes.
  • Fully automatic bug filing and closing for issue trackers (Monorail only for now).
  • Testcase minimization.
  • Regression finding through bisection.
  • Statistics for analyzing fuzzer performance, and crash rates.
  • Easy to use web interface for management and viewing crashes.
  • Firebase authentication.
  • Support for coverage guided fuzzing (e.g. libFuzzer and AFL) and blackbox fuzzing.



You can find detailed documentation here.


As of January 2019, ClusterFuzz has found ~16,000 bugs in Chrome and ~11,000 bugs in over 160 open source projects integrated with OSS-Fuzz.

Getting Help

You can file an issue to ask questions, request features, or ask for help.

Staying Up to Date

We will use clusterfuzz-announce(#) to make announcements about ClusterFuzz.

comments powered by Disqus