Balancer DeFi Protocol Suffers $128M Hack – Largest Exploit in Its History
- What Happened in the Balancer Hack?
- How Did the Exploit Unfold?
- Why Is This Balancer’s Worst Hack Yet?
- Market Fallout: BAL and ETH Take a Hit
- What’s Next for Balancer?
- Key Takeaways for DeFi Users
- FAQs: Balancer Hack Explained
In a shocking turn of events, Balancer, one of DeFi's most established protocols, was hacked on November 3, 2025, losing over $128 million due to precision errors and flawed access controls in its V2 pools. The attack, the largest in Balancer’s history, has sent shockwaves through the crypto space, with the BAL token plummeting 8% and ethereum also taking a hit. This incident adds to 2025’s grim tally of $2.2 billion in crypto hacks so far, raising serious questions about DeFi security.
What Happened in the Balancer Hack?
On November 3, 2025, at 7:48 AM UTC, Balancer’s V2 pools were exploited, resulting in a staggering $128.64 million loss. Blockchain analytics firm Nansen flagged suspicious outflows: 6,850 osETH (~$26.9M), 6,590 WETH (~$24.5M), and 4,260 wstETH (~$19.3M) were drained within minutes. The attack spread across Ethereum (where $99M was stolen), Arbitrum, Base, and five other chains. Balancer’s team quickly paused vulnerable pools, but the damage was done.
How Did the Exploit Unfold?
The hacker exploited a combination of precision/rounding errors in V2 pool swap calculations and a critical access control flaw in Boosted Pools. By manipulating thefunction, they bypassed pool invariants (mathematical rules governing swaps) and withdrew funds without proper authorization. Cross-chain vulnerabilities worsened the fallout, as Balancer operates on multiple blockchains. Notably, V3 pools remained untouched—small consolation for users.
Why Is This Balancer’s Worst Hack Yet?
This isn’t Balancer’s first rodeo: in 2020, it lost $500K to deflationary token quirks, and in 2023, $1M vanished from Boosted Pools. But the 2025 breach dwarfs both, becoming the protocol’s largest loss and a top-three DeFi hack this year. With $2.2B already stolen in 2025, crypto is on track for its worst year ever security-wise. As one BTCC analyst put it, “Even audited giants aren’t immune—DeFi’s attack surface keeps expanding.”
Market Fallout: BAL and ETH Take a Hit
The BAL token dropped 8% to $0.91, while Ethereum (already in a post-bull-run slump) fell another 8%. Projects relying on Balancer V2 now face $60M+ in at-risk TVL. Traders on exchanges like BTCC scrambled to adjust positions, and fear spread across DeFi Twitter. “This is why I keep my liquidity in hardware wallets,” joked one crypto vet—dark humor, but a sign of shaken confidence.
What’s Next for Balancer?
Balancer’s team is investigating and collaborating with security firms to trace the stolen funds (currently being consolidated for laundering). No recoveries have been announced. The protocol’s reputation took a blow, but its V3 infrastructure survived—a silver lining. Meanwhile, the hack underscores a brutal truth: in DeFi, code is law, and even a single loophole can cost millions.
Key Takeaways for DeFi Users
1.Avoid overexposure to any single protocol.
2.Even audited code can fail (Balancer was reviewed by top firms).
3.Follow Balancer’s official channels for recovery plans.
4.As the BTCC team notes, “2025’s hack trend shows no sign of slowing.”
FAQs: Balancer Hack Explained
How much was stolen in the Balancer hack?
$128.64 million, making it Balancer’s largest-ever exploit.
Which chains were affected?
Ethereum ($99M loss), Arbitrum, Base, and five others.
Did V3 pools get hacked?
No—only V2 pools were compromised.
What caused the exploit?
Precision errors in swaps + faulty access controls in Boosted Pools.
Is my Balancer V2 LP at risk?
If in paused pools, no—but check Balancer’s official updates.
