Mozilla tested Anthropic’s Claude Mythos and found the model could identify hundreds of vulnerabilities, with Mythos flagging 271 issues in Firefox 150 after Mozilla’s earlier Opus 4.6 scan led to fixes for 22 security-sensitive bugs in Firefox 148. Anthropic is restricting access through Project Glasswing amid misuse concerns and reports of unauthorized access, while Mozilla says LLMs now rival elite human researchers and defenders must adapt. #ClaudeMythos #Firefox
Keypoints
- Claude Mythos identified 271 vulnerabilities in Firefox 150.
- Opus 4.6 scans helped Mozilla fix 22 security-sensitive bugs in Firefox 148.
- Anthropic’s models now match elite human researchers at finding complex vulnerabilities.
- Anthropic is not publicly releasing Mythos and launched Project Glasswing for limited access.
- Reports emerged of unauthorized access to Mythos the same day Anthropic announced limited testing access.
Read More: https://www.helpnetsecurity.com/2026/04/22/claude-mythos-mozilla-vulnerabilities-scanning/