They exploited a flaw in the set-up of OpenAI’s community forum, which is hosted by a third-party, Discourse, and used it to gain access to internal sign-ons and eventually an OpenAI employee’s ChatGPT account. This ChatGPT account had access to internal code through GitHub.

“We thank the researchers for contacting us and sharing their findings,” OpenAI said, adding that it had fixed the issues. Anthropic declined to comment. Hacktron did not immediately respond.

The disclosure on Thursday, first reported by The Wall Street Journal, came as Anthropic published a new set of data that showed a rapid increase in how much the lab used AI to develop its new models.

It said 26 percent of research and development work was “led by” its Claude model, up from 1 percent in March, meaning that AI completed the majority of tasks based on human instruction and under supervision.

The company said that as AI systems become more powerful, they were “increasingly being used to build the next version of themselves.”

Anthropic said it shared the data to help the public “understand how close the world is to reaching recursive self-improvement,” the point at which AI can train and improve itself or new models.

This threshold is at the heart of concerns that AI systems will become more difficult to oversee, leading to a loss of human control.

Its models did not yet operate fully autonomously for any of the research it studied, Anthropic added. On 90 percent of tasks, AI “collaborates” with a human and does large chunks of work.

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