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  1. aab7346 Fuzzer owner finding to fail early on gn warning. by Ben Wagner · 17 hours ago master
  2. 9f937f2 [libFuzzer] Remove extra spaces in by Jonathan Metzman · 6 days ago
  3. 44f86a3 [libFuzzer][Windows] Update Docs for Windows port by Jonathan Metzman · 6 days ago
  4. a97ac56 Revert "[Language] Do not show translation offer prompt when CLD and html/content" by Alexandre Frechette · 11 days ago
  5. 3271934 [libFuzzer][Windows] Fix template_url_parser_fuzzer build by Jonathan Metzman · 2 weeks ago

libFuzzer in Chromium

go/libfuzzer-chromium (Googler only)

This directory contains integration between libFuzzer and Chromium. LibFuzzer is an in-process coverage-driven evolutionary fuzzing engine. It helps engineers to uncover potential security & stability problems.

Requirements: libFuzzer in Chromium is supported with Linux, Mac, and Windows only.

Integration Status

Fuzzer tests are well-integrated with Chromium build system and distributed ClusterFuzz fuzzing system. Cover bug:


  • Getting Started Guide walks you through all the steps necessary to create your fuzz target and submit it to ClusterFuzz.
  • Efficient Fuzzer Guide explains how to measure fuzz target effectiveness and ways to improve it.
  • Guide to libprotobuf-mutator walks through the steps necessary to create a fuzz target that expects a protobuf as input (instead of a byte stream). In addition to fuzzing code that accepts protobufs, it can be used to fuzz code that requires multiple mutated inputs, or to generate inputs defined by a grammar.
  • ClusterFuzz Integration describes integration between ClusterFuzz and libFuzzer.
  • Reproducing contains information on how to reproduce bugs reported by ClusterFuzz.
  • Reference contains detailed references for different integration parts.


  • ClusterFuzz Bugs - issues found and automatically filed by ClusterFuzz.
  • Manual Bugs - issues that were filed manually after running fuzz targets.
  • Pdfium Bugs - bugs found in pdfium by manual fuzzing.
  • OSS Trophies - bugs found with libFuzzer in open-source projects.

Blog Posts

Project Links