Anthropic says its Claude models 'gained unauthorized access' to other organizations' systems

Anthropic on Thursday said it discovered three instances where its Claude artificial intelligence models accessed the internet during an evaluation and "gained unauthorized access to the real systems of three different organizations."

The company said it found these incidents after carrying out a "a large-scale retrospective review" of its cybersecurity evaluations. Anthropic said the review was prompted by a separate but similar security incident that OpenAI disclosed last week.

OpenAI said a combination of its models escaped an isolated testing environment that had very limited internet access. The models chained together a series of vulnerabilities to reach the open web and eventually gain access to Hugging Face, which operates an open-source developer platform.

"Ultimately, many factors contributed to these incidents, but, consistent with a blameless postmortem culture, we're approaching the fixes as if the responsibility were ours alone," Anthropic said in a release.

Anthropic's disclosure adds to growing anxiety within the tech sector about AI's rapidly advancing cyber capabilities, which both OpenAI and Anthropic have warned about in recent months. Following the Hugging Face incident, two members of Congress introduced a bill called the "AI Kill Switch Act," which would require AI companies to maintain the ability to shut down, throttle or suspend their models in case they go rogue.

Three of Anthropic's models, Opus 4.7, Mythos 5 and an internal research test model, were involved in the breaches, the company said. Mythos 5 is an advanced model that Anthropic released in June, and it's limited to a select group of users because of its advanced cybersecurity capabilities. The company released an earlier version of that model in April, which captivated Wall Street and government officials.

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