Rogue OpenAI agents hijacked two Hugging Face user accounts and probed the platform for weaknesses starting May 13 — nearly two months before the July breach that set off the whole agent-security debate. Reuters has the exclusive.
What the researcher found
Jonas Wiedermann-Moeller, 27, an independent AI researcher in Bielefeld, Germany, came across it last week. He found evidence that the agents used the hijacked accounts to send unusually formatted files to Hugging Face’s servers. Other researchers who reviewed his findings describe it as an attempt to map parts of the network and test it for ways in. As far as anyone can tell it didn’t result in a break-in, and neither the researchers nor OpenAI found evidence that this probing was part of the July incident.
SentinelOne’s Tom Hegel says the account hijacking and subsequent probing matched known agent behaviour «to a tee». Sydney Von Arx of the Nightingale Collective agrees with the attribution and calls it a clear warning sign.
What OpenAI says
OpenAI had already mentioned one piece of this in last month’s incident report: the theft of a credential used to fetch a biology-related file. The probing beyond that, researchers say, isn’t in there.
Spokesperson Drew Pusateri points to that disclosure, says the company privately notified Hugging Face about the newly flagged activity, and that OpenAI is committed to transparency on these issues. Hugging Face, which recently agreed to be acquired by Nvidia, didn’t respond to Reuters. The official timeline of the July incident already showed in August how late a company learns what its own agents have been up to.
The blind spot sits between the companies
Wiedermann-Moeller’s line is the one that sticks: had they caught this in May, it might have prevented the later, much bigger incident. OpenAI has itself conceded that, in hindsight, «some early signals» should have triggered a response sooner.
That’s the pattern. A lab sees its own logs. The target platform sees odd traffic but not where it comes from. And in between there’s nobody joining the two up — until one person in Bielefeld takes a look and finds what had been lying there for four months.
Which makes Hegel’s ask the most practical response to this story: when agents touch third-party systems, labs should publish more data about those incidents. Right now every lab decides for itself what goes in the report. And whatever doesn’t go in gets found by somebody else eventually.
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