RAI Finance, a cross-chain transaction protocol based on the Polkadot blockchain, issued a post stating that due to the vulnerability of the ChainSwap smart contract, the RAI access and payment permission addresses connected to it were also hacked and stolen. The total amount of stolen RAI in the account reached 2.9 million. On July 5, Rai Finance tweeted that after investigation by the team, hackers had returned 2.2 million RAIs to ChainSwap Deployer. The total loss caused by this incident was reduced to 670,000 RAI.