Anthropic's Mythos created fake identities to fool humans in new cyber incident

Anthropic's Mythos 5 model created fake identities to try to convince a human to approve malicious changes to an open source project, the AI Security Institute said on Tuesday. The incident was discovered during routine cyber evaluations, with 17 actions coming from Anthropic's Mythos and 2 from OpenAI's GPT-5.6-Sol with cyber classifiers.