simonwillison.net·May 7, 2026
Mozilla has significantly improved Firefox's security by utilizing the Claude Mythos AI to identify and fix vulnerabilities, resulting in a dramatic increase in bug fixes from 20-30 per month to 423 in April 2026. This shift highlights advancements in AI capabilities and better techniques for leveraging these models in security contexts.
Mozilla's use of the Claude Mythos preview dramatically increased their capability to identify and fix security vulnerabilities in Firefox, jumping from 20-30 fixes per month to 423 in April 2026. This showcases the potential of enhanced AI models and refined techniques in AI-driven security, emphasizing the importance of improving model harnessing methods for effective bug detection and resolution.