What Is a Common Example of a Major Reentrancy Attack in Cryptocurrency History?

The most famous example is The DAO attack in 2016 on the Ethereum network. The attacker exploited a vulnerability in the withdrawal function, repeatedly calling it before the contract's state could update the balance.

This allowed the attacker to drain millions of Ether from The DAO. This critical event led to a hard fork of the Ethereum blockchain to recover the stolen funds.