Mozilla Fixes Record 423 Firefox Bugs in One Month

Mozilla disclosed that it repaired 423 Firefox vulnerabilities in April after deploying an agentic AI pipeline around Anthropic’s Claude Mythos Preview; the AI identified 271 bugs (180 classified as high-severity), including long-standing and complex issues like a 20-year-old heap use-after-free and sandbox escapes. The team credits a middleware “agentic harness” that forces reproducible PoC tests, and Mozilla plans to integrate the pipeline into CI; the report also notes debate over whether restricted high-end models outperform cheaper alternatives.