Atheris

Atheris is a coverage-guided Python fuzzing engine. It supports fuzzing of Python code, and also of native extensions written for CPython. Atheris is based on libFuzzer.

A fuzz test is a Python function that receives the generated data; helper classes turn the raw bytes into integers, strings or other values. When fuzzing native code, Atheris can be combined with AddressSanitizer or UndefinedBehaviorSanitizer to catch additional bugs. Prebuilt wheels installed with pip include a built-in libFuzzer, which is sufficient for Python code; building from source matches the libFuzzer version with the installed Clang for native extensions. It supports Linux and macOS.

Atheris is developed by Google and is free and open source under the Apache 2.0 licence.