Submission Details
Impact:
Likelihood:
Denial of Service in NFT Mint Loop and hence Minting Fails
# Denial of Service in NFT Mint Loop and hence Minting Fails
## Description
* Normally, minting functions should limit the number of iterations or allow controlled batching to avoid exceeding block gas limits.
* The current implementation of `mintSnowman` performs a **loop based on an arbitrary `amount`** without any upper bound or batching logic. This creates a **Denial of Service (DoS) risk** if a large `amount` is passed, as the transaction may exceed the block gas limit and always revert.
```solidity
function mintSnowman(address receiver, uint256 amount) external {
for (uint256 i = 0; i < amount; i++) {
@> _safeMint(receiver, s_TokenCounter);
emit SnowmanMinted(receiver, s_TokenCounter);
s_TokenCounter++;
}
}
```
## Risk
**Likelihood**:
* This occurs when a large `amount` is passed to `mintSnowman`.
**Impact**:
* Makes it impossible to mint NFTs in one transaction when `amount` is too large.
* Could halt onboarding or claiming process if not handled properly.
## Proof of Concept
The following solidity example simulates a Denial Of Service which exceeds block gas limit and hence the transaction reverts
```solidity
// Simulate a large mint causing out-of-gas
snowman.mintSnowman(attacker, 1_000_000); // Likely to exceed block gas limit and revert
```
## Recommended Mitigation
Add a **reasonable upper limit** on the `amount` or enforce a **batching strategy**.
```diff
function mintSnowman(address receiver, uint256 amount) external {
+ if (amount > 10) {
+ revert("Too many NFTs in one mint");
+ }
for (uint256 i = 0; i < amount; i++) {
_safeMint(receiver, s_TokenCounter);
emit SnowmanMinted(receiver, s_TokenCounter);
s_TokenCounter++;
}
}
```
This protects against denial-of-service due to gas exhaustion while still enabling bulk minting in controlled sizes.
Rewards breakdown
nSLOC
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100 EXP
20 EXP
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