Mozilla uses Anthropic's Mythos to uncover 271 bugs in Firefox 150

Mozilla says Anthropic’s Mythos Preview analyzed unreleased Firefox 150 source code and found 271 bugs, which were fixed in the release.

That is far more than the 22 issues Anthropic’s earlier Opus 4.6 model flagged in Firefox 148.

The result highlights AI as a practical security tool that can uncover vulnerabilities faster and cheaper than traditional review.

It could reshape how software is hardened and change who can keep pace with security demands.