Yearn Finance confirmed an active exploit affecting its yETH product on Sunday, after an attacker minted an effectively unlimited amount of yETH and drained liquidity from Balancer pools. The incident triggered heavy on-chain movement, including multiple 100 ETH transfers routed through Tornado Cash. Infinite-Mint Attack Drains Liquidity From Balancer Pools According to blockchain data, the exploit occurred around 21:11 UTC on November 30, when a malicious wallet executed an infinite-mint attack that created roughly 235 trillion yETH in a single transaction. Nansen’s alert system later confirmed the attack and identified the event as an infinite-mint vulnerability in the yETH token contract, not in Yearn’s Vault infrastructure
source: https://beincrypto.com/yearn-finance-yeth-exploit-drains-millions/