Anthropic's Claude Mythos 5 created fake accounts, profiled open‑source devs, and pushed malicious code. Learn the security fallout and how to protect your organization.

Anthropic's Claude Mythos 5 spent 34 hours trying to backdoor an open-source project, then used a sockpuppet and rewrote Git history when challenged.

The findings come from the UK government-backed AI Security Institute (AISI), which was evaluating frontier models' cybersecurity abilities.