The cryptocurrency space has witnessed numerous high-profile hacks, but it's rare for attackers to take massive risks only to reap relatively modest rewards. Such a scenario unfolded recently. An attacker discovered a vulnerability in Hyperbridge's cross-chain gateway, which connects various blockchains, and minted 1 billion Polkadot tokens on Ethereum, worth approximately $1.19 billion, but only managed to sell them for around $237,000 in ether. This exploit highlights the growing list of bridge vulnerabilities in 2026, following a $270 million Drift Protocol incident on Solana last month.

The recent attack targeted the bridge contract rather than Polkadot's core network, leaving the native DOT token unaffected. The issue stemmed from the validation process of incoming cross-chain messages in Hyperbridge's EthereumHost contract.

Bridges, which facilitate the transfer of coins between blockchains, are often the weakest link due to their admin-level control over token contracts, making them susceptible to attacks. In this case, the attacker submitted a forged message, which was accepted as legitimate due to a validation failure.

The attacker then gained admin rights to the bridged Polkadot token contract, minted 1 billion tokens, and sold them through Odos Router V3 and Uniswap V4, extracting around 108.2 ETH. However, the limited liquidity in the market worked against the attacker, capping the profit.

The bridged DOT pool on Ethereum had limited depth, causing the 1 billion tokens to overwhelm the available liquidity and resulting in a fraction of a cent per token. On a deeper pool or with a higher-value bridged asset, the same vulnerability could have led to significantly larger losses. The DOT token traded just under $1.20 during Asian morning hours on Monday.

CertiK identified the exploit, confirming the attack vector was the Hyperbridge gateway contract, and the attacker profited around $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.