Mozilla used a new AI tool called Claude Mythos to find 271 security problems in Firefox, and all of them have been fixed in Firefox version 150.
The team built a special testing system to verify the AI's work. This ensured almost none of the reports were false alarms, as the AI creates simple test pages that run on a special test version of Firefox where a crash proves a real bug
The fixed bugs include 180 very serious issues, 80 medium issues, and 11 small issues.