Submission Details
Severity:
`approve()/safeApprove()` may revert if the current approval is not zero
Summary
Vulnerability Details
Calling approve() without first calling approve(0) if the current approval is non-zero will revert with some tokens, such as Tether (USDT). While Tether is known to do this, it applies to other tokens as well, which are trying to protect against this attack vector. safeApprove() itself also implements this protection.
Always reset the approval to zero before changing it to a new value (SafeERC20.forceApprove() oes this for you), or use safeIncreaseAllowance()/safeDecreaseAllowance()
Tools Used
Manual Review
Recommendations
Updates
Prize pool breakdown
Total prize
22,500 USDC
nSLOC
1,05421 USDC / LOC
20,000 USDC
2,500 USDC
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