Command line used to find this crash: afl-fuzz -i src -o outputs -- ./src/giftcardreader 1 @@ If you can't reproduce a bug outside of afl-fuzz, be sure to set the same memory limit. The limit used for this fuzzing session was 0 B. Need a tool to minimize test cases before investigating the crashes or sending them to a vendor? Check out the afl-tmin that comes with the fuzzer! Found any cool bugs in open-source tools using afl-fuzz? If yes, please drop an mail at once the issues are fixed https://github.com/AFLplusplus/AFLplusplus