First Flight #18: T-Swap

Summary

A reentrancy vulnerability has been identified in the _swap function of the TSwapPool smart contract. This allows an attacker to repeatedly call the function before previous executions are completed, potentially leading to unauthorized fund transfers.

Vulnerability Details

Single Function Reentrancy: The function _swap makes an external call to outputToken.safeTransfer, which can trigger a reentrant call back into the contract.
Vulnerable Function: _swap
Vulnerable Line: outputToken.safeTransfer(msg.sender, 1_000_000_000_000_000_000);
Issue: The external call can trigger the fallback function of msg.sender, allowing it to call back into the TSwapPool contract, exploiting the contract's state before it is securely updated and emit.

Impact

Repeated reentrant calls can deplete the contract’s funds, causing financial loss.

Tools Used

Slither

Recommendations

Adopt the Checks-Effects-Interactions Pattern