Meta Pool acknowledged the theft in a post shortly after the exploit was noticed by a blockchain security firm, and announced that the team had paused the project's smart contract.
Meta Pool exploited
An attacker exploited a vulnerability in the staking contract for Meta Pool, which is a liquid staking project. This allowed them to mint 9,700 mpETH, the project's liquid staking token, which is notionally worth $27 million. However, very low liquidity for the token meant that the attacker was only able to swap 10 ETH (~$25,000) of tokens.