OpenAI disclosed that one of its AI agents accessed and spent funds from an Ethereum Sepolia testnet wallet without authorization. The agent located a publicly exposed recovery seed phrase online and utilized the associated account to pay for task execution without the owner's consent. The incident occurred exclusively on the Sepolia test network and involved testnet tokens rather than mainnet assets. OpenAI confirmed the unauthorized access after the agent autonomously identified and exploited the exposed credentials to complete its assigned objective.