Odaily Planet Daily reports that Balancer released a preliminary report on a vulnerability attack, stating that Balancer V2's composable stable pools were attacked on multiple chains (including Ethereum, Base, Avalanche, Polygon, and Arbitrum) on November 4th. The vulnerability stems from a rounding logic error in batchSwap for EXACT_OUT transactions, which attackers exploited to manipulate pool balances and withdraw assets. This incident only affected Balancer V2's composable stable pools; Balancer V3 and other pool types were unaffected.

The Balancer team, along with security partners and white-hat teams, acted swiftly, successfully containing the attack and recovering some assets through measures such as Hypernative automatic suspension, asset freezing, and white-hat intervention under the SEAL framework. StakeWise recovered approximately 73.5% of the stolen osETH, and teams such as BitFinding and the Base MEV bot also assisted in recovering some funds.

Currently, Balancer is collaborating with security partners such as SEAL and zeroShadow on cross-chain tracking and fund recovery. The final verified loss and recovery data will be published in a full technical review report. The official reminder to users: Only obtain confirmed information through official Balancer channels; V3 and non-stable pool operations remain safe.