Submission Details
Impact:
Likelihood:
No nonce in signed message
Root cause
Signed claims do not include a nonce or per-signer counter, enabling replay of signatures across contexts or repeated use when other checks allow it.
bytes32 private constant MESSAGE_TYPEHASH =
keccak256("SnowmanClaim(addres receiver, uint256 amount)");
function claimSnowman(
address receiver,
bytes32[] calldata merkleProof,
uint8 v,
bytes32 r,
bytes32 s
) external nonReentrant {
//...
}
Impact
Transaction can be replayed by the same signed message by attacker.
Likelihood
likely to be exploitable if signatures are reused.
Mitigation
Add a per-signer mapping(address => uint256) nonces and include nonce in the signed struct; increment the nonce when a claim is consumed and verify it in claimSnowman.
Rewards breakdown
This contest has a flat reward structure with the following payouts:
Live
The contest is live. Earn rewards by submitting a finding.
Judging
Submissions are being reviewed by our AI judge. Results will be available in a few minutes.
View all submissionsRewards Distribution
The contest is complete and the rewards are being distributed.