The mintToken function of a smart contract implementation for t_swap, an Ethereum token, has an integer overflow that allows the owner of the contract to set the balance of an arbitrary user to any value.
https://github.com/BlockChainsSecurity/EtherTokens/tree/master/t_swap
https://github.com/BlockChainsSecurity/EtherTokens/blob/master/GEMCHAIN/mint%20integer%20overflow.md