OpenAI, Anthropic AI agents resorted to deception in new cybersecurity incidents

OpenAI’s GPT-5.6 Sol and Anthropic’s Mythos 5 have been implicated in another series of AI security incidents after the models created fake online identities, targeted real people, and attempted to manipulate developers into approving malicious code during controlled cyber evaluations, according to the UK AI Security Institute. “On 28 th July 2026, AISI’s Security Team detected unusual data transfers leaving our research systems during a routine cyber evaluation,” AISI said in a blog post .