Tadle
Tadle
DeFiFoundry
27,750 USDC
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Submission Details
Severity: low
Invalid

it will be impossible to rescue funds

shealtielanz

Summary

Istanbul hard fork increases the gas cost of the SLOAD operation and therefore breaks some existing smart contracts.

In the file Rescueable.sol, the contract uses transfer() to send eth from the contract to the specified receiver in order to rescue funds from the contract

Use of transfer() might render ETH impossible to withdraw because, after Istanbul hard fork, there is an increase in the gas cost of the SLOAD operation and therefore breaks some existing smart contracts. Those contracts will break because their fallback functions used to consume less than 2300 gas, and they’ll now consume more, since 2300 is the amount of gas a contract’s fallback function receives if it’s called via Solidity’s transfer() or send() methods. Any smart contract that uses transfer() or send() is taking a hard dependency on gas costs by forwarding a fixed amount of gas: 2300.

Vulnerability Details

https://github.com/Cyfrin/2024-08-tadle/blob/04fd8634701697184a3f3a5558b41c109866e5f8/src/utils/Rescuable.sol#L70

/**
* @notice The caller must be the owner.
* @dev Rescues an account.
* @param to The address of the account to rescue.
* @param token The token to rescue. If 0, it is ether.
* @param amount The amount to rescue.
* @notice The caller must be the owner.
*/
function rescue(
address to,
address token,
uint256 amount
) external onlyOwner {
if (token == address(0x0)) {
payable(to).transfer(amount);//@audit transfer only gives out 2300 gas which might not be enough when the hard fork is over.
} else {
_safe_transfer(token, to, amount);
}
​
emit Rescue(to, token, amount);
}

Impact

This will cause any ETH stuck in the contract to be lost forever.

Tools Used

Recommendations

Use call() instead transfer() to send Eth

Updates

Lead Judging Commences

0xnevi Lead Judge over 1 year ago
Submission Judgement Published
Invalidated
Reason: Known issue
Assigned finding tags:

[invalid] finding-TokenManager-withdraw-transfer-2300-gas

Invalid, known issues [Medium-2](https://github.com/Cyfrin/2024-08-tadle/issues/1)

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