For more than two decades, Firefox has been one of the most scrutinized and security-hardened codebases on the web. Open source means our code is visible, reviewable, and continuously stress-tested by a global community. A few weeks ago, Anthropic’s Frontier Red Team approached us with results from a new AI-assisted vulnerability-detection method that surfaced more than a dozen verifiable security bugs, with reproducible tests. Our engineers validated the findings and landed fixes ahead of the r...