AI-Assisted Fuzzing: Generating libFuzzer Harnesses with a Local LLM

Writing the harness is the friction that keeps most codebases from ever being fuzzed. This walkthrough puts an offline open-weights model behind that job: it drafts a libFuzzer harness for a vulnerable C record parser, clang compiles it with AddressSanitizer, and the binary reports a genuine stack-buffer-overflow with a symbolized frame on the offending memcpy. From there it scales to what real…