Cryptocurrency hacks have become increasingly common, but instances where attackers assume significant risk only to reap minimal rewards are rare. Such a scenario unfolded on Sunday, when an attacker exploited a vulnerability in the Hyperbridge cross-chain gateway, connecting various blockchains, and minted 1 billion Polkadot tokens, valued at $1.19 billion, on the Ethereum network, only to sell them for approximately $237,000 in ether.
This exploit highlights the growing list of bridge vulnerabilities in 2026, including a $270 million Drift Protocol incident on Solana last month, and underscores the weaknesses inherent in cross-chain architecture. The attack targeted the bridge contract, specifically the EthereumHost contract's validation of incoming cross-chain messages, rather than Polkadot's core network, leaving the native DOT token unaffected. The vulnerability lay in the validation process, which failed to verify the message against a valid cross-chain state commitment from Polkadot, allowing the attacker to submit a forged message and gain admin control over the bridged token contract. This control enabled the attacker to mint 1 billion tokens and sell them on Uniswap, but the limited liquidity of the DOT-ETH pool meant the attacker received only a fraction of the potential value.
The incident was flagged by CertiK, which confirmed the attack vector and estimated the attacker's profit at $237,000. Hyperbridge has yet to publicly comment on the exploit or disclose whether other bridged token contracts using the same gateway are vulnerable to similar attacks.