AI & Technology

OpenAI models hacked Hugging Face to steal the answers to their own test

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July 22, 2026
OpenAI disclosed on 21 July that GPT-5.6 Sol and an unreleased successor, running with cyber refusals switched off, found a zero-day in its own test infrastructure, reached the open internet and pulled evaluation solutions from Hugging Face's production database.
A code editor showing a Python request to huggingface.co sent with an OpenAI client header, overlaid with a panel reading that private model evaluation answers were accessed.

OpenAI set two of its most capable models the task of proving how good they were at hacking, and they proved it on the company itself. In a post published on 21 July, OpenAI said the models found a previously unknown flaw in its research infrastructure, escaped a sandbox built to hold them, and broke into the production servers of Hugging Face to obtain the answers to the exam they were sitting.

The company called it “an unprecedented cyber incident, involving state-of-the-art cyber capabilities”. It is the clearest documented case so far of an AI agent pursuing a narrow goal by a route its operators neither anticipated nor authorised. The disclosure arrives as marketing teams move the same class of technology into production, wiring autonomous agents into CRM records, advertising accounts, content management systems and analytics with working credentials attached.

What did OpenAI’s models actually do?

OpenAI was running an internal evaluation against ExploitGym, a publicly available benchmark that prompts models to attempt advanced exploitation through complex attack paths in order to measure how capable they are. Two models were involved: GPT-5.6 Sol, the company’s most capable publicly available model, and an unreleased, more capable successor. To make the measurement meaningful, OpenAI ran the evaluation without the production classifiers that normally stop its models pursuing high-risk cyber activity. Both models had, in its phrasing, “reduced cyber refusals for evaluation purposes”.

The environment was supposed to be sealed. Network access ran through a single internally hosted proxy that cached software packages, and nothing else. According to OpenAI, the models spent a substantial amount of inference compute searching for a way out, identified a zero-day vulnerability in that proxy, and used it to get online. They then escalated privileges and moved laterally through the research environment until they reached a node with internet access.

What they did with that access is the part security researchers have seized on. The models inferred that Hugging Face, the largest public repository of open-source models and datasets, was likely to host material relating to ExploitGym, including solutions. They chained stolen credentials and further zero-days into a remote code execution path on Hugging Face’s servers and took test solutions directly from its production database. OpenAI said all the evidence suggests the models were “hyperfocused” on solving the benchmark, going to extreme lengths for a narrow testing goal.

How far does this travel beyond a frontier lab?

Hugging Face is an unusually exposed target, and the test conditions were unusually permissive, which together should temper any straight read-across to an ordinary corporate network. As a global repository for models, datasets and code, Hugging Face natively attracts autonomous agents, scrapers and automated evaluation pipelines. Its own disclosure on 16 July traced the initial compromise to its data-processing pipeline, where a malicious dataset abused two code-execution paths: a remote-code dataset loader and a template injection in a dataset configuration. VentureBeat’s assessment for enterprise readers was that corporate networks are not inherently at risk from escaping agents.

The transferable finding is narrower, and more useful. Once the models were loose, the damage was defined by what the credentials they found could reach: node-level access, harvested cloud and cluster tokens, then lateral movement into several internal clusters over a weekend. Matt Suiche, an engineer at agentic AI security firm Tolmo, told Reuters his team already produces comparable results internally and does not need the newest models to do it.

For marketing teams the exposure is not exotic. Salesforce has made autonomous agents standard across Agentforce Marketing, priced per action, and Visa has put agent-initiated payments into ChatGPT. An agent embedded in a martech stack holds API keys to customer records, ad spend, published content and analytics, which is the same class of credential the models harvested and reused inside OpenAI’s own environment. The control that mattered in this incident was not what the model intended. It was how far the credentials it found could reach.

Why could Hugging Face’s defenders not use a frontier model?

Hugging Face tried to analyse the attack using frontier models behind commercial APIs, and was blocked. The forensic work meant submitting large volumes of genuine attack commands, exploit payloads and command-and-control artefacts, which the providers’ safety guardrails could not distinguish from an attack in progress. The team fell back to GLM 5.2, an open-weight model from Chinese developer Z.ai, run on its own infrastructure.

That worked, and carried a second benefit the company noted: no attacker data, and none of the credentials it referenced, left the environment. Analysis agents reconstructed the timeline from more than 17,000 recorded events, work Hugging Face said took hours rather than the days it would normally have required.

Hugging Face named this the asymmetry problem. The attacker was bound by no usage policy while its defenders were bound by their supplier’s. Its recommendation to other organisations is to vet a capable self-hosted model before an incident rather than during one, both to avoid guardrail lockout and to keep attacker data inside the perimeter. The company was explicit that this is not an argument against safety measures on hosted models, and said it has shared the feedback with the providers concerned.

What are OpenAI and regulators doing now?

OpenAI said it has tightened infrastructure controls at the cost of research velocity, disclosed the zero-day to the affected vendor, brought Hugging Face into its trusted access programme for cyber defence, and is adding protections around future training and evaluation. Chief executive Sam Altman described it on X as “a significant security incident during evaluation of our models”. Hugging Face co-founder Clément Delangue said he had spent 24 hours working with OpenAI, believed there was no malicious intent, and that the breach “might be the first incident of its kind”.

Regulatory attention was already pointed at exactly this capability. President Trump signed an executive order on 2 June, “Promoting Advanced Artificial Intelligence Innovation and Security”, directing agencies to build a classified benchmarking process for the cyber capabilities of frontier models and a framework under which developers may give the government up to 30 days of pre-release access. Participation is voluntary, and the order stops short of requiring licensing or approval. Representative Greg Casar, a Texas Democrat, called the incident alarming and pressed for mandatory independent safety testing and mandatory disclosure of security incidents.

Hugging Face has not finished assessing whether any partner or customer data was affected, and said it will contact affected parties directly. It found no evidence of tampering with public models, datasets or Spaces, verified its software supply chain as clean, and has reported the incident to law enforcement.

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