PANews reported on August 14th that Venn Network security researcher deeberiroz reported, according to The Block, that Coinbase lost approximately $300,000 due to a misconfigured interaction between Coinbase and the 0x project's "switcher" contract. In response, Coinbase Chief Security Officer Philip Martin stated that no customer funds were affected and that this was an isolated incident.
The 0x project provides an "exchanger," a contract designed specifically for performing swaps. This contract is permissionless and can be called by anyone to perform arbitrary operations, regardless of ownership restrictions. Because this contract is permissionless, the bot appears to have called the exchanger contract to perform a transfer, transferring approved tokens from the Coinbase wallet to their own addresses.