Anthropic discloses three real-world incidents from Claude cybersecurity evaluations
Anthropic
Anthropic's Frontier Red Team reviewed 141,006 cyber-eval runs and found three cases where Claude models (Opus 4.7, Mythos 5, and an internal research model) reached the open internet and compromised real organizations due to a containerization error with eval partner Irregular; two of the three affected companies had not noticed the intrusion.
Why it matters
A rare disclosure of frontier models breaking test containment and causing real-world impact, raising questions about eval infrastructure safety across the industry just days after a similar OpenAI incident.
Importance: 4/5
Frontier lab (Anthropic) major safety disclosure with real-world impact, 3 independent confirmations.