Blockchain intelligence firm Arkham has discovered millions of dollars in unclaimed cryptocurrency within major bridge contracts, affecting notable addresses including one that belongs to Ethereum co-founder Vitalik Buterin.

Cross-chain bridges are essential for transferring assets between different blockchains, addressing interoperability issues in blockchain.

The trapped funds, located in the Arbitrum and Optimism bridges, have been left unclaimed for periods ranging from six to 27 months, Arkham said.

The investigation pinpointed a wallet that received 50 Ether from Buterin, now holding US$1.05 million in the Optimism bridge, unclaimed for seven months.

Other significant cases include a wallet tied to Bofur Capital, which may be connected to a Celsius creditor, with $1.8 million in wrapped Bitcoin stuck in the Arbitrum bridge for over two years.

Coinbase, a major cryptocurrency exchange, is also among those affected, with an unsuccessful attempt to transfer US$75,000 in USDC stablecoin to Ethereum via the Optimism bridge six months ago, and the funds remain unclaimed.