Mozilla says Mythos and others helped it identify many Firefox security bug fixes (www.techradar.com)

Mozilla has successfully leveraged Anthropic's Mythos, a cutting-edge AI tool, to identify and patch over 400 security vulnerabilities in Firefox in April 2026 alone. Mythos stands out from traditional AI fuzzing tools by significantly reducing false positives, thanks to a custom harness developed by Mozilla. This harness allows the AI to analyze Firefox code effectively, filtering out the "unwanted slop" typical of previous models. By providing Mythos with specific files that contain known issues, it can generate effective test cases for detecting vulnerabilities that might otherwise take weeks or even years to identify using conventional methods. The significance of this development lies in Mythos's ability to uncover complex security flaws that had persisted for 15 to 20 years, demonstrating its potential to reshape the landscape of cybersecurity. While Mythos represents an impressive advancement in AI capability, it underscores that human guidance remains crucial for maximizing its effectiveness. This partnership between Mozilla and Mythos highlights the promise of AI in aiding cybersecurity efforts, while also reminding the community that AI should complement rather than replace human expertise in tackling intricate security challenges.