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  1. c2f04eb Relativize paths in build files by Tom Anderson · 3 days ago master
  2. 6b96bef Move chromium-specific QUIC code from net/quic/chromium/ to net/quic/. by Ryan Hamilton · 2 weeks ago
  3. bc687db build: Remove sanitizer_keep_symbols and sanitizer_no_symbols flags. by Peter Collingbourne · 2 weeks ago
  4. 4628e50 [fuzzer] Add attributes to LLVMFuzzerInitialize definition by Andreas Haas · 3 weeks ago
  5. bd4b9af Reland "[LPM] Improve process for using the plugin for LITE_RUNTIME." by Jonathan Metzman · 4 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 earlier.

Requirements: libFuzzer in Chromium is supported with Linux and Mac 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