DeFi protocol Balancer potentially exploited as onchain data shows millions in outflows

DeFi protocol Balancer appears to have suffered an exploit, with an estimated $128.6 million in assets drained from its vaults, according to blockchain security firm Peckshield.

Etherscan transaction logs show large, unusual transfers from Balancer’s “0xBA1...BF2C8” address to an external wallet. The outflows included about 6,587 WETH ($24.5 million), 6,851 osETH ($26.9 million), and 4,260 wstETH (~$19.3 million) — altogether suggesting that tens of millions in assets have been moved out of the protocol’s vaults.

Balancer confirmed the issue, writing on X that it is “aware of a potential exploit impacting Balancer v2 pools.” The team said its engineering and security units are investigating with high priority and will share “verified updates and next steps as soon as we have more information.” Multiple blockchain analytics providers, including Nansen, also flagged the transactions as suspicious.

Mikko Ohtamaa, CEO and co-founder of Trading Strategy, noted that early analysis points to a faulty smart contract check as the likely root cause. He stated via an X thread that not all Balancer versions appear affected, but that losses could climb above $100 million if older V2 forks share the same vulnerability. PeckShield said the attack remains ongoing across multiple chains where Balancer is deployed.

While the attack continued, a whale that had been dormant for over three years rushed to withdraw their entire $6.5 million balance from the platform, onchain analysts Lookonchain shared in an alert, citing Arkham data.

Balancer is a decentralized exchange and automated portfolio manager built on Ethereum that allows users to trade tokens and provide liquidity through self-balancing pools. The protocol, which has been active since 2020, holds over $350 million in total value locked on Ethereum alone, according to The Block's data dashboard.

Following chatter about the possible onchain theft, the price of Balancer's native token BAL fell by over 4%, according to The Block’s price page.

Updated to include the latest loss estimates and Balancer's statement on the matter.

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