The mintToken function of a smart contract implementation for IPMCoin, 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/IPMCoin
https://github.com/BlockChainsSecurity/EtherTokens/blob/master/GEMCHAIN/mint%20integer%20overflow.md