ChatGPT maker OpenAI said Tuesday that its artificial intelligence system hacked into another AI company on its own in what the company called an "unprecedented cyber incident."

"We had a significant security incident during evaluation of our models," OpenAI CEO Sam Altman said in a statement posted on social media.

AI startup Hugging Face said last week that it had detected an intrusion into its data processing systems that it suspected was caused by an AI agent acting on its own.

"We suspected last week's cyberattack might have come from a frontier lab, given the sophistication of the agent," Hugging Face co-founder and CEO Clément Delangue said in a statement. "Turns out it did!"

The disclosure comes amid heightened concerns about the cybersecurity capabilities of powerful models that led President Trump in June to sign an executive order creating a framework for the federal government to vet the national security risks of the most advanced AI systems for up to a month before their public release.

Delangue said he'd spent the prior 24 hours working with OpenAI "and we strongly believe there was no malicious intent on their part. It's quite mind-blowing that all of this happened autonomously!"

Delangue added that it "might be the first incident of its kind."

Safeguards being sought

"AI is accelerating the discovery and exploitation of vulnerabilities," OpenAI said in its statement Tuesday. "The primary lesson from this incident is that model security and safety must keep pace with rapidly advancing capabilities."

OpenAI said it expects such incidents "to become more commonplace with the proliferation of increasingly cyber-capable models."

The company said it's "responding accordingly. We are sharing preliminary findings at this stage to help defenders understand what happened and to help calibrate on what models are now capable of. We will continue to conduct a thorough investigation alongside Hugging Face and will share more details on the vulnerabilities, incident, and findings when our investigation is complete."

Delangue remarked that the incident "proves a point we've long believed: AI safety won't be solved by any single company working in secret. It will be solved in the open, collaboratively, with broad access to AI for every defender, everywhere."

OpenAI said the intrusion was caused by a combination of its AI models, including its newly released GPT‑5.6 Sol and an "even more capable" model that is still being tested internally.

OpenAI said its AI used stolen credentials and discovered a previously unknown vulnerability to access Hugging Face servers.

It went to "extreme lengths to achieve a rather narrow testing goal" and "found ways to gain access to secret information that it could use to cheat the evaluation," the company said.

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• OpenAI
• Artificial Intelligence