“I found that Claude’s fuzzer is able to trigger the out-of-bounds read and write bugs only.”
Claude wrote a nice fuzzer for GIF, a format all over its training data. Murray gave it a made-up format from a 2016 student assignment with five seeded bugs. The fuzzer hid the valid instructions behind random noise and always wrote the correct length field, so the Heartbleed-style bug could never fire. It found two of five, which is what you get when the model has never seen the answer.