Bid Beasts
First Flight #49
Beginner FriendlyFoundrySolidityNFT
100 EXP
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Submission Details
Severity: low
Valid

Event Emitting Error

kevin1115

Root + Impact

Description

  • In the Buy Now Logic branch

    AuctionSettled is already emitted within _executeSale , so no additional emission is needed

    The current code emits AuctionSettled after require(msg.sender != previousBidder, ...) , which is logically incorrect because the auction has not yet ended and the NFT has not yet been transferred.

function placeBid(uint256 tokenId) external payable isListed(tokenId) {
Listing storage listing = listings[tokenId];
address previousBidder = bids[tokenId].bidder;
uint256 previousBidAmount = bids[tokenId].amount;
​
require(listing.seller != msg.sender, "Seller cannot bid");
​
require(listing.auctionEnd == 0 || block.timestamp < listing.auctionEnd, "Auction ended");
​
​
if (listing.buyNowPrice > 0 && msg.value >= listing.buyNowPrice) {
uint256 salePrice = listing.buyNowPrice;
uint256 overpay = msg.value - salePrice;
​
bids[tokenId] = Bid(msg.sender, salePrice);
listing.listed = false;
​
if (previousBidder != address(0)) {
_payout(previousBidder, previousBidAmount);
}
​
// @Notice: AuctionSettled is already emitted within _executeSale , so there's no need to emit it again..
_executeSale(tokenId);
​
if (overpay > 0) {
_payout(msg.sender, overpay);
}
​
return;
}
​
require(msg.sender != previousBidder, "Already highest bidder");
// @Notice: The current code emits AuctionSettled after require(msg.sender != previousBidder, ...) , which is logically incorrect because the auction hasn't ended yet and the NFT hasn't been transferred
emit AuctionSettled(tokenId, msg.sender, listing.seller, msg.value);

Risk

Likelihood:

  • The Regular Bidding Logic branch will directly trigger AuctionSettled, which will make people mistakenly think that the auction has been completed

Impact:

  • The monitoring program misjudged the transaction, and others would stop bidding.

Proof of Concept

​

Recommended Mitigation

Delete emit AuctionSettled(tokenId, msg.sender, listing.seller, msg.value); on line 143 and let the _executeSale function handle all settlement-related event emissions
Updates

Lead Judging Commences

cryptoghost Lead Judge 2 months ago
Submission Judgement Published
Validated
Assigned finding tags:

BidBeasts Marketplace: Incorrect Event Emission

placeBid emits AuctionSettled even though the auction hasn’t ended, causing misleading event logs.

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