Mozilla, the nonprofit behind the Firefox browser, reported that its early access to Anthropic's unreleased Claude Mythos Preview model led to the discovery of hundreds of security flaws. The company fixed 423 bugs in April, a dramatic increase from 25 in January. One vulnerability had persisted for 20 years, undetected by conventional security-testing tools known as fuzzers.
This breakthrough marks a significant leap in AI's ability to identify software weaknesses. Mozilla previously found that earlier AI systems produced unreliable results, which it termed "slop." The new model's success suggests a maturation of large language models for cybersecurity applications, where precision is critical.