yETH Pool Drained in One Transaction

The attack, which took place on Monday, targeted Yearn Finance’s yETH product — a vault designed to aggregate liquid staking derivatives into a single asset. Blockchain data shows that the exploiter used a vulnerability that enabled the minting of infinite yETH tokens, which were then used to withdraw millions of dollars worth of assets from Balancer pools.

The attack was first noticed by X user Togbe, who detected unusual activity while monitoring the transactions. The yETH pool was reported to hold around $11 million before the exploit. Yearn Finance quickly confirmed the incident and stated that its V2 and V3 vaults were not affected. The protocol announced that a detailed investigation was underway in collaboration with SEAL 911 and ChainSecurity.

Technical Details and Initial Findings

The attack was executed using several newly created smart contracts, some of which self-destructed after the transactions were completed. Yearn Finance’s latest update confirmed a total loss of $9 million $8 million drained from the stableswap pool and $0.9 million removed from the yETH-WETH pool on Curve. The Yearn team emphasized that no other products in their codebase were affected by this vulnerability.

Community Reaction and Implications for DeFi Security

The incident sparked mixed reactions within the community. Some users expressed concerns about older contract architectures and warned that similar vulnerabilities may exist in other products as well. Yearn Finance previously experienced a major hack in 2021 involving its yDAI vault, resulting in an $11 million loss. Additionally, in December 2023, a faulty script wiped 63% of a treasury position.

This latest exploit highlights growing security concerns in the DeFi sector. A major Balancer hack in 2025—one of similar technical complexity—resulted in losses exceeding $116 million.

Crypto Hack Losses Exceed $127 Million in November

According to CertiK’s monthly security report, the losses in November alone include:

• $127 million lost due to hacks and exploits
• $172 million total value of funds initially affected
• Net losses decreased by ~$45 million after recovered funds

DeFi protocols accounted for the majority of the losses, while exchange hacks contributed approximately $29.8 million.

Experts commented:

“The yETH attack is yet another example of how complex and vulnerable DeFi products can be. A single flaw can cause millions of dollars in losses within seconds, underscoring the importance of stronger code audits.”

Conclusion

The attack on Yearn Finance’s yETH product has once again highlighted the significant security risks within the DeFi ecosystem. The draining of the pool in a single transaction exposed critical weaknesses in smart contract infrastructure. Yearn’s confirmation of a $9 million loss underscores the severity of the incident, while the funds laundered through Tornado Cash make the investigation more challenging. With DeFi hacks in recent months surpassing hundreds of millions of dollars, the urgency for enhanced security-focused development continues to intensify.

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What is Yearn.finance? (YFI)

Yearn.finance (YFI) is a DeFi protocol running on Ethereum blockchain. This protocol focuses on optimizing earnings on crypto assets and allows users to increase their incomes.

YFI includes a set of protocols operated with codes. APY data table shows interest rates in different lending protocols, while Earn offers users the highest interest rates possible by lending their assets.

Vaults include various investment strategies designed to achieve the highest return from other DeFi projects, while Zap enables users to save costs and workload by combining multiple transactions with a single click.

Users earn YFI tokens by locking their crypto assets into specific contracts on the yearn.finance platform. This method is part of a practice known as “yield farming”. Users are rewarded with more tokens by locking their crypto assets in DeFi protocols.

Yearn.finance has shown rapid growth since its inception and has secured a significant place in the DeFi ecosystem. This platform offers a range of opportunities for users to optimize their crypto assets and increase their income.

How Does Yearn.finance Work?

Yearn.finance works with protocols distributed to the Ethereum blockchain and these protocols run on other decentralized exchanges like Balancer and Curve. Users expect these protocols to offer their services on Ethereum and fulfill the promised functions.

The platform’s main services, Earn, Zap, and APY, focus on allowing users to lend or trade their cryptocurrencies. Earn scans different lending protocols to find the best interest rates and offers those advantages to users. Users can benefit from the specified interest rates by investing their assets in yearn.finance.

Who Created Yearn.finance?

Yearn.finance was launched in 2020 by an independent developer named Andre Cronje.

In particular, Cronje has indicated that he did not take any funding for the yearn.finance protocol nor did he reserve any tokens for himself prior to launching the platform. This separates yearn.finance from most other DeFi projects.

Tokenomics

YFI is the cryptocurrency that manages the yearn.finance platform.

YFI owners can vote on proposals to set the rules that platform users must follow. A proposal must receive more than 50% of the vote to be implemented in yearn.finance’s code.

YFI Token can easily be bought and sold on Global Exchanges such as Binance, BitGet, Kucoin, Mexc, HTX and Gate.io. If you want to benefit from the discount link specifically defined for Coin Engineer followers, you can use our reference code by clicking on the exchange you want to register.

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