oss-fuzz-gen icon indicating copy to clipboard operation
oss-fuzz-gen copied to clipboard

LLM powered fuzzing via OSS-Fuzz.

A Framework for Fuzz Target Generation and Evaluation

This framework generates fuzz targets for real-world C/C++ projects with various Large Language Models (LLM) and benchmarks them via the OSS-Fuzz platform.

More details available in AI-Powered Fuzzing: Breaking the Bug Hunting Barrier: Alt text

Current supported models are:

  • Vertex AI code-bison
  • Vertex AI code-bison-32k
  • Gemini Pro
  • OpenAI GPT-3.5-turbo
  • OpenAI GPT-4

Generated fuzz targets are evaluated with four metrics against the most up-to-date data from production environment:

  • Compilability
  • Runtime crashes
  • Runtime coverage
  • Runtime line coverage diff against existing human-written fuzz targets in OSS-Fuzz.

Here is a sample experiment result from 2024 Jan 31. The experiment included 1300+ benchmarks from 297 open-source projects.


Overall, this framework manages to successfully leverage LLMs to generate valid fuzz targets (which generate non-zero coverage increase) for 160 C/C++ projects. The maximum line coverage increase is 29% from the existing human-written targets.

Note that these reports are not public as they may contain undisclosed vulnerabilities.


Check our detailed usage guide for instructions on how to run this framework and generate reports based on the results.


Interested in research or open-source community collaborations? Please feel free to create an issue or email us: [email protected].

Bugs Discovered

So far, we have reported 3 new bugs/vulnerabilities found by automatically generated targets built by this framework:

Project LLM Prompt template
cJSON Vertex AI default
libplist Vertex AI default
hunspell Vertex AI default

Current top coverage improvements by project

Project Coverage increase % *
tinyxml2 29.84
inih 29.67
lodepng 26.21
libarchive 23.39
cmark 21.61
fribidi 18.20
lighttpd 17.56
libmodbus 16.59
valijson 16.21
libiec61850 13.53
hiredis 13.50
cmake 12.62
pugixml 12.43
meshoptimizer 12.23
libusb 11.12
json 10.84

* Percentage coverage is calculated using a denominator of the total lines of source code compiled during the OSS-Fuzz build process for the entire project.