The Hyperbridge exploit from April 13 turned out to be far more severe than initially reported, with total losses now revised to around $2.5 million. Early estimates placed the damage at roughly $237,000, but deeper forensic analysis across multiple chains revealed a much larger impact.

According to the team, the discrepancy came from overlooked factors like incentive pool losses and cross-chain activity. What initially looked like a single exploit was actually a two-phase attack. First, the attacker drained around 245 ETH from the Token Gateway contract. Then, roughly an hour later, they minted nearly 1 billion bridged DOT tokens and dumped them into liquidity pools across networks like Ethereum, Arbitrum, Base, and BNB Chain.

The root cause was traced to a vulnerability in the Merkle Mountain Range proof verification logic, allowing unauthorized minting and fund extraction. The incident highlights how complex cross-chain systems can amplify risks, especially when exploits span multiple networks and liquidity sources simultaneously.