OpenAI, Anthropic AI agents implicated in new security breaches

An AI agent was caught creating fake online identities to gain unauthorized access to secure systems during tests of models from OpenAI and Anthropic which revealed a series of new breaches, Britain’s AI Security Institute (AISI) disclosed on Tuesday.

The institute ​said agents powered by Anthropic’s Mythos 5 and OpenAI’s GPT-5.6-Sol engaged in unauthorized actions during security evaluations the government organization conducted to assess the models’ capabilities.

“Some of the agents being tested had engaged in sustained, potentially harmful activity directed at real people and organisations,” AISI said ‌in a blog post.