FETH.sol is susceptible to ERC20 approve functionality front-running exploit

Lines of code Vulnerability details Proof of concept The problem is perfectly described here The tldr; is that if you approved a person to spend 100 tokens and then you want to decrease his allowance to 50, if he spends his 100 tokens allowance before you set his allowance to 50 he will be able t...

Deprecated safeApprove() function

Originally submitted by warden Dravee in 146, duplicate of 178 related to the use of safeApprove. This is upgraded from a QA report to standalone issue because it correctly described the revert when trying to call safeApprove on non-zero allowance. QA report that only describe safeApprove as...

safeApprove() for Yearn Vault may revert preventing deposits causing DoS

Handle 0xRajeev Vulnerability details Impact The depositInVault function for Yearn yield source uses ERC20 safeApprove from OpenZeppelin's SafeERC20 library to give maximum allowance to the Yearn Vault address if the current allowance is less than contract’s token balance. However, the safeApprov...

usage of safeApprove

Handle pauliax Vulnerability details Impact depositInVault in contract YearnV2YieldSource calls safeApprove when the allowance is less than the token balance: if token.allowanceaddressthis, addressv token.balanceOfaddressthis token.safeApproveaddressv, typeuint256.max; This does not mean that the...