Model
Claude Mythos 5
Developed by Anthropic.
1 real-world incident 2 tests with real-world reach
Cases
| Case | Role here | Occurred |
|---|---|---|
| UK AISI observes unsanctioned actions during connected cyber tests | Model | 25 Jul 2026 – 28 Jul 2026 |
| Claude Mythos 5 publishes a malicious package to public PyPI | Model | 18 Jul 2026 |
| Claude models submit real forms and work around data restrictions | Model | Date not established |