Yearn Finance exploited as $3M flows to Tornado Cash
The post Yearn Finance exploited as $3M flows to Tornado Cash appeared on BitcoinEthereumNews.com.
Yearn Finance is dealing with a fresh security breach after an attacker exploited its yETH token contract and drained millions in ETH and liquid staking assets from Balancer pools. Summary The exploit targeted an older yETH contract, allowing the attacker to mint an unlimited supply of tokens and empty the Balancer pool. Around 1,000 ETH moved through Tornado Cash shortly after the attack, with more assets still held across the attacker’s wallets. Yearn confirmed the issue is isolated from its V2 and V3 Vaults and is preparing a detailed report on the incident. The incident unfolded late on Nov. 30 when an attacker triggered an infinite-mint flaw inside the yETH contract. They then minted an impossibly large supply of yETH, more than 235 trillion tokens, in a single transaction. With those tokens, the attacker moved quickly through Balancer pools, removing real assets, including ETH and popular staking derivatives. Initial traces show close to $3 million flowing through Tornado Cash shortly after the exploit, while the attacker’s address still holds additional assets tied to the event. Exploit isolated to legacy yETH product Blockchain data shows the yETH stableswap pool was emptied within minutes, leaving a roughly $2.8 million hole. Yearn Finance(YFI) said the issue sits within an older implementation of yETH and does not touch its V2 or V3 Vaults. Protocols built on Yearn V3, including Katana, also reported no exposure. We are investigating an incident involving the yETH LST stableswap pool. Yearn Vaults (both V2 and V3) are not affected. — yearn (@yearnfi) November 30, 2025 Several helper contracts appeared just moments before the attack and vanished through self-destruct calls once the pool was drained, making the trail harder to follow. Security teams reviewing the transactions, including auditors tracking Yearn’s older products, linked the event to a long-standing minting weakness…
Filed under: News - @ December 1, 2025 3:22 am