Mystic Finance RWA Security Review — Second June 2025 Review

Description

The protocol maintains a global variable currentWithheldETH to represent the amount ofETHreservedforuserwithdrawalsaftertheycallunstake(). However, thisvariableisonlydecreased

when withdraw() is called — not when unstake() is made. This creates a critical race condition: multiple users can initiate unstake() relying on the same currentWithheldETH balance, leading to overcommitment. If one user completes the withdrawal first, the remaining users are blocked from withdrawing, resulting in a denial of service (DoS). Example Scenario Initial State: currentWithheldETH = 10 ETH Alice calls unstake(10 ETH) → succeeds (as 10 ETH is available) Bob calls unstake(8 ETH) → also succeeds (still sees 10 ETH as available) Both transactions pass the currentWithheldETH >= amount check, since the variable hasn’t been decremented yet. Alice calls withdraw() first: Receives 10 ETH currentWithheldETH becomes 0 Bob then calls withdraw(): Fails, as there is no remaining currentWithheldETH Additionally, Bob cannot call unstake() again due to the presence of an active withdrawal request If no one deposits or triggers a stake rebalance before Bob’s cooldown period ends, Bob is temporary locked out of his funds until admin calls unstakeGov() or rebalance happens.