Core Contracts
Regnum Aurum Acquisition Corp
HardhatReal World AssetsNFT
77,280 USDC
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Submission Details
Severity: low
Invalid

Incorrect value emitted in event when rebalancing the Lending Pool liquidity

crunter

Summary

After perform the rebalance of the Lending Pool liquidity, the LiquidityRebalanced event is emitted. The event is supposed to include the current amount of liquidity in the buffer, however, this value is not updated after the rebalance, resulting in a wrong value emitted.

Vulnerability Details

The LiquidityRebalanced event definition is the following:

> ILendingPool.sol
​
/**
* @notice Emitted when liquidity is rebalanced
* @param bufferAmount The amount of liquidity in the buffer
* @param vaultAmount The amount of liquidity in the Curve vault
*/
event LiquidityRebalanced(uint256 bufferAmount, uint256 vaultAmount);

However, when emitted after the liquidity rebalancing, only the second parameter has the updated value, while the amount of liquidity in the buffer still reflects an old value.

> LendingPool.sol
​
function _rebalanceLiquidity() internal {
// if curve vault is not set, do nothing
if (address(curveVault) == address(0)) {
return;
}
​
uint256 totalDeposits = reserve.totalLiquidity; // Total liquidity in the system
uint256 desiredBuffer = totalDeposits.percentMul(liquidityBufferRatio);
@> uint256 currentBuffer = IERC20(reserve.reserveAssetAddress).balanceOf(reserve.reserveRTokenAddress);
​
if (currentBuffer > desiredBuffer) {
uint256 excess = currentBuffer - desiredBuffer;
// Deposit excess into the Curve vault
_depositIntoVault(excess);
} else if (currentBuffer < desiredBuffer) {
uint256 shortage = desiredBuffer - currentBuffer;
// Withdraw shortage from the Curve vault
_withdrawFromVault(shortage);
}
​
// @audit - totalVaultDeposits value is updated in the _depositIntoVault/_withdrawFromVault functions.
// However, currentBuffer still has the old value
​
@> emit LiquidityRebalanced(currentBuffer, totalVaultDeposits);
}

Impact

Impact: Low

Multiple associated services may display incorrect values, potentially misleading protocol administrators and consumers.

Likelihood: Medium

Tools Used

Manual Review

Recommendations

This issue is present even if liquidity rebalancing process is not correctly performed. It is recommended to update the current amount of liquidity in the buffer to reflect the most recent value in the LiquidityRebalanced event.

> LendingPool.sol
​
function _rebalanceLiquidity() internal {
// if curve vault is not set, do nothing
if (address(curveVault) == address(0)) {
return;
}
​
uint256 totalDeposits = reserve.totalLiquidity; // Total liquidity in the system
uint256 desiredBuffer = totalDeposits.percentMul(liquidityBufferRatio);
uint256 currentBuffer = IERC20(reserve.reserveAssetAddress).balanceOf(reserve.reserveRTokenAddress);
​
if (currentBuffer > desiredBuffer) {
uint256 excess = currentBuffer - desiredBuffer;
// Deposit excess into the Curve vault
_depositIntoVault(excess);
} else if (currentBuffer < desiredBuffer) {
uint256 shortage = desiredBuffer - currentBuffer;
// Withdraw shortage from the Curve vault
_withdrawFromVault(shortage);
}
​
+ currentBuffer = IERC20(reserve.reserveAssetAddress).balanceOf(reserve.reserveRTokenAddress);
​
emit LiquidityRebalanced(currentBuffer, totalVaultDeposits);
}
Updates

Lead Judging Commences

inallhonesty Lead Judge 7 months ago
Submission Judgement Published
Validated
Assigned finding tags:

LendingPool::_rebalanceLiquidity emits an event with stale buffer

Invalidated by appeal in 1090

inallhonesty Lead Judge 7 months ago
Submission Judgement Published
Validated
Assigned finding tags:

LendingPool::_rebalanceLiquidity emits an event with stale buffer

Invalidated by appeal in 1090

Appeal created

inallhonesty Lead Judge 6 months ago
Submission Judgement Published
Invalidated
Reason: Design choice
Assigned finding tags:

LendingPool::_rebalanceLiquidity emits an event with stale buffer

Invalidated by appeal in 1090

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