Extending Ruzzy with LibAFL
Summary
Ruzzy, a coverage-guided fuzzer (a tool that tests code by generating random inputs and tracking which parts of the code get executed) for Ruby, was updated to support LibAFL, a more advanced and actively maintained fuzzing library written in Rust, by building LibAFL as a standalone library and allowing it to be specified via an environment variable instead of Clang's default fuzzer library.
Solution / Mitigation
The source explicitly describes the implementation approach: build LibAFL's libFuzzer.a as a standalone library using the provided build.sh script in a Dockerfile, then modify Ruzzy's fuzzer_no_main library detection to prioritize an environment variable (FUZZER_NO_MAIN_LIB) that specifies the path to the LibAFL libFuzzer.a file, falling back to Clang's defaults if the variable is not set. The key code change checks if the environment variable is present, validates the file exists, and uses it; otherwise, it searches for Clang's built-in fuzzer_no_main libraries as a fallback.
Classification
Original source: https://blog.trailofbits.com/2026/04/29/extending-ruzzy-with-libafl/
First tracked: April 29, 2026 at 08:00 AM
Classified by LLM (prompt v3) · confidence: 95%