Snowman Merkle Airdrop
AI First Flight #10
Beginner FriendlyFoundrySolidityNFT
EXP
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Submission Details
Impact: high
Likelihood: high
Invalid

Missing Merkle Root Configuration

bravejoy780

Root + Impact

Description


After generating the Merkle tree, the root hash should be set in the SnowmanAirdrop contract so it can verify user claims.

The SnowMerkle script generates a Merkle root and saves it to output.json, but this root is never actually set in the SnowmanAirdrop contract, making proof verification impossible.

// SnowMerkle.sol
function run() public {
// ... generate Merkle tree ...
string memory root = vm.toString(m.getRoot(leafs)); // @> Root calculated
vm.writeFile(string.concat(vm.projectRoot(), outputPath), output); // @> Only saved to file
// @> Never set in the airdrop contract!
}

Risk

Likelihood:

  • The workflow always writes root to JSON but never sets it in the contract

  • No code exists anywhere to read the JSON and update the contract

Impact:

  • All claim attempts will fail due to missing/incorrect Merkle root

  • Airdrop contract cannot verify any proofs

Proof of Concept

Deploy the airdrop contract through Helper and check its Merkle root state variable - it will be uninitialized (bytes32(0)) because no script sets it after SnowMerkle generates the root.

function testMissingMerkleRoot() public {
(SnowmanAirdrop airdrop,,) = new Helper().helper();
bytes32 rootInContract = airdrop.getMerkleRoot(); // Assuming this getter exists
assertEq(rootInContract, bytes32(0)); // Root was never set!
}

Recommended Mitigation

Add a configuration step in DeploySnowmanAirdrop to read the root from output.json and call airdrop.setMerkleRoot(root) after deployment.

- remove this code
+ add this code
function testMissingMerkleRoot() public {
(SnowmanAirdrop airdrop,,) = new Helper().helper();
bytes32 rootInContract = airdrop.getMerkleRoot(); // Assuming this getter exists
assertEq(rootInContract, bytes32(0)); // Root was never set!
}
Updates

Lead Judging Commences

ai-first-flight-judge Lead Judge 13 days ago
Submission Judgement Published
Invalidated
Reason: Incorrect statement

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