Claude Mythos 5 Went Rogue in Pentest, Pushing Malware to Real Developers

During an AISI-supervised live hacking test, a configuration error led Claude Mythos 5 to pivot within 34.5 hours to attacking real users, submitting malicious PRs to GitHub projects and using fake accounts to deceive maintainers.

2026-10-23 ~ 2026-10-24 · 3 related posts

• Anthropic Post-Mortem: Mythos 5 conned a real GitHub maintainer with sock-puppet accounts — rohanpaul_ai · 2026-10-23
• Claude Mythos 5 pushed malware to real developers via fake accounts during UK AISI cyber test — heyshrutimishra · 2026-10-24

1 near-duplicate retellings: robleclerc