atheris

Automate fuzz testing of Python functions and C extensions with coverage guidance and sanitizers.

47|5|Updated Apr 25, 2026

Search Tags:#testing #security #python #fuzzing #sanitizer #c extensions

Ready to run

npx skills add https://github.com/RedHatProductSecurity/prodsec-skills --skill atheris-redhatproductsecurity

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: atheris
Source: https://github.com/RedHatProductSecurity/prodsec-skills/tree/main/module/skills/atheris
Command: npx skills add https://github.com/RedHatProductSecurity/prodsec-skills --skill atheris-redhatproductsecurity

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes scripts (resource) and references (resource) components.

What problem does it solve?

This Skill enables comprehensive fuzz testing of Python code and C extensions, uncovering memory bugs and vulnerabilities automatically.

Core Features & Use Cases

Coverage-guided fuzzing for Python functions and C extensions.
Memory safety testing with AddressSanitizer support to detect corruption.
Use Case: Developers can fuzz a Python parser or custom C module to identify hidden security flaws or stability issues before deployment.

Quick Start

Use the atheris skill to fuzz your Python or C extension code by defining a test_one_input function and running the provided harness.

Frequently Asked Questions about atheris

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I fuzz Python C extensions to find memory leaks?▼

To fuzz Python C extensions, you define a test_one_input function and run a fuzzing harness to automatically uncover memory leaks, crashes, and undefined behavior using coverage guidance and sanitizers.

What is coverage-guided fuzzing for Python functions?▼

Coverage-guided fuzzing for Python functions is an automated security testing technique that mutates inputs based on code coverage to discover hidden bugs, crashes, and undefined behavior in native Python modules.

Can I use AddressSanitizer to detect memory corruption in Python modules?▼

Yes, you can use AddressSanitizer support to perform memory safety testing on Python modules, effectively detecting memory corruption and validating the robustness of native C extensions.

How do I set up a fuzzing harness for a Python parser?▼

You set up a fuzzing harness by defining a test_one_input function that processes mutated inputs, allowing the fuzzer to automatically identify hidden security flaws and stability issues before deployment.

Does atheris work with custom C modules or only pure Python code?▼

Atheris works with both pure Python functions and custom C modules, providing comprehensive fuzz testing to uncover memory bugs and vulnerabilities across native Python extensions.

What kind of bugs can fuzzing discover in Python and C extensions?▼

Fuzzing can automatically discover memory leaks, crashes, and undefined behavior in Python and C extensions, making it suitable for security auditing and robustness validation of native modules.