DeFi Platform Balancer Suffers $129M Hack as Berachain Halts Network for Hard Fork

Highlights:

• Balancer suffers $129M hack after attackers drained assets from v2 pools across several blockchain networks.
• Bera Foundation has halted its network for a hard fork to recover funds affected by the Balancer exploit.
• Security experts traced the breach to a faulty smart contract check that enabled unauthorized swaps across chains.

Balancer confirmed a major exploit that drained more than $129 million from its v2 pools on November 3. The decentralized finance protocol said its engineering and security teams are investigating the incident. Blockchain security firms PeckShieldAlert and Spot On Chain flagged large outflows from Balancer vaults across several chains.

#PeckShieldAlert @balancer has been drained ~$70.8M worth of cryptos, including 6,851.12 $osETH (~$27M), 6,587.44 $WETH (~$24.5M) & 4,259.84 $wstETH (19.3M) https://t.co/mcmlPnJDaM pic.twitter.com/j3KJXV7pd3

— PeckShieldAlert (@PeckShieldAlert) November 3, 2025

The attack impacted Ethereum, Base, Optimism, Polygon, Sonic, and Berachain networks. Hackers attacked liquidity pools and emptied assets such as WETH, osETH, wstETH, sfrxETH, and rsETH. PeckShield estimated that the largest losses occurred on Ethereum, where a majority of the vaults are hosted. Spot On Chain data showed the attackers converted the stolen tokens into ETH in real time.

Shortly after the attack, a dormant whale address withdrew $7.38 million worth of assets from Balancer. On-chain analysts linked the movement to growing fears among users after the exploit. Balancer stated that it is prioritizing user protection while working with external auditors to determine the root cause. The team confirmed it would release verified updates once the investigation is complete.

Balancer Suffers $129M Hack Linked to Smart Contract Flaw

According to blockchain researchers, the exploit began as a smart contract vulnerability in the v2 vaults of Balancer. The weakness was inappropriate authorization and callback processing, where hackers could corrupt vault calls when pooling is being initialized. This vulnerability allowed rogue swaps and balance adjustments that emptied accounts in several chains.

Trading Strategy CEO Mikko Ohtamaa said a faulty contract check was likely the main cause of the breach. He noted that not all Balancer versions appear affected. However, other forks using the same code base could face similar exposure. PeckShield confirmed that the attack remains ongoing across chains where Balancer is deployed.

An OG Ethereum DEX Balancer got rekt for ~$70M.

GM.

Root cause (kudos to Defimon Signals) was a faulty check.

Still not clear what Balancer versions are affected, but not all of them. https://t.co/eVfRugvZlO pic.twitter.com/Ao6CkU0BFk

— Mikko Ohtamaa (@moo9000) November 3, 2025

Data from Etherscan showed large outflows from Balancer’s main wallet “0xBA1…BF2C8” to external addresses. Transactions included 6,587 WETH worth $24.5 million, 6,851 osETH valued at $26.9 million, and 4,260 wstETH worth $19.3 million. Blockchain analytics firms Nansen and Arkham also flagged the transfers as suspicious.

Users hurried to withdraw money as the attack advanced. Another wallet, which DeFi tracker Lookonchain described as inactive in the last three years, took out more than $6.5 million from the protocol. Balancer, founded in 2020, functions as a decentralized exchange and automated portfolio manager. The platform currently holds more than $350 million in total value locked on Ethereum alone.

A whale 0x0090, dormant for 3 years, just woke up after the #Balancer exploit — rushing to withdraw all $6.5M from the #Balancer.

If you still have funds on #Balancer, ⚠️ take action and secure them now.https://t.co/ocNGGobPEd pic.twitter.com/nnR5td0DmZ

— Lookonchain (@lookonchain) November 3, 2025

Berachain Network Halted as Core Teams Contain Exploit Impact

The Bera Foundation said validators deliberately paused the Berachain network to protect users. The team announced an emergency hard fork to patch vulnerabilities linked to the Balancer v2 exploit. It added that the network will resume operations once recovery measures are complete.

The Berachain validators have coordinated to purposefully halt the Berachain network as the core team performs an emergency hard fork to address Balancer V2 related exploits on the BEX.

This halt has been executed purposefully, and the network will be operational shortly upon…

— Berachain Foundation 🐻⛓ (@berachain) November 3, 2025

Smokey The Bera, a core developer, confirmed on X that the Ethena team disabled bridging out of Berachain. He added that lending markets and deposits for USDe were also paused. Furthermore, HONEY minting and redemption were halted, while centralized exchanges were contacted to blacklist suspicious addresses.

This is not Balancer’s first security breach. Two years ago, the protocol suffered a $1 million stablecoin exploit after revealing a critical vulnerability. The year before, hackers compromised its website through a phishing attack and stole $238,000 worth of crypto. In 2020, Balancer lost $500,000 in a flash loan attack that exploited a deflationary token mechanism. The Balancer team has not yet confirmed if user funds will be reimbursed. However, the coordinated response from affected networks suggests that recovery efforts are underway.