Hackers exploited vulnerabilities in the Balancer decentralized finance protocol on November 3, 2025, stealing an estimated $120 million to $128 million in cryptocurrency. Balancer confirmed the incident and paused affected pools to mitigate further losses. Security firms traced the attack to compromised access control mechanisms.
The exploit targeted Balancer, a DeFi protocol active since 2020 that holds more than $350 million in Ethereum value. On Monday, November 3, 2025, the incident began in the early morning, with hackers pilfering funds primarily in ETH, amounting to at least $99 million of the total losses estimated at over $120 million by most blockchain security firms, including PeckShield and Cyvers. One report specified $128 million stolen.
Balancer issued a statement on X: "We’re aware of a potential exploit impacting Balancer v2 pools. Our engineering and security teams are investigating with high priority. We’ll share verified updates and next steps as soon as we have more information." The company explained that faulty access control mechanisms allowed attackers to manipulate balances directly. Cyvers CEO Deddy Lavid stated, “The ongoing drain likely stems from a compromise of access control mechanisms within the protocol, allowing the attackers to manipulate balances directly.”
In response, Balancer paused pools that could be paused and placed them in recovery mode, though ties to other platforms prevented unilateral pauses for all affected assets. The protocol, which has undergone about 10 audits and maintained bug bounties, committed to user safety and is working with security and legal teams for a thorough investigation and post-mortem.
Several linked organizations acted swiftly: The Berachain Foundation halted its network and froze some stolen funds. Platforms like Gnosis, Sonic, and Beefy implemented similar protective measures. Balancer warned users against fraudulent messages circulating from impostor accounts.
This incident follows a $10.8 million theft from Garden Finance last week and contributes to a year of heightened crypto crime. Chainalysis reported over $2 billion stolen in the first half of 2025, with $2.17 billion year-to-date, surpassing 2024 totals. Much of the theft is linked to North Korean actors, who stole at least $1.65 billion from January to September 2025, funding ballistic missile programs.