Many OpenSea users were shocked to find that their valuable NFTs had been sold for next to nothing earlier this week. Many users were shocked to find that out, with an OpenSea user who goes by TBALLER on Monday tweeted, “I just lost an ape guys…. I’m crying…. How did this just happen????” adding 15 crying emojis.
TBALLER saw their Bored Ape Yacht Club (BAYC) NFT get sold for around $1,800 on OpenSea 99% below the floor price due to a user interface (UI) issue on the NFT marketplace. The buyer who poached the NFT then resold it immediately for nearly $200,000, making a profit of $198,000 within an hour.
The issue is not new but it resurfaced in a big way this week. Blockchain analytics firm Elliptic identified at least three attackers who purchased more than eight NFTs worth over $1 million for much less than their market value on Monday.
Those NFTs were from collections such as BAYC, Mutant Ape Yacht Club, Cool Cats, and CyberKongz. One attacker gained 332 ether (worth over $800,000) by purchasing NFTs below market value due to the issue, according to blockchain security firm PeckShield.
An OpenSea spokesperson told The Block that the company is “actively reaching out to and reimbursing affected users” who saw their NFTs get sold below market value due to the “confusing UI” issue. At the same time, the marketplace is trying its best to solve the problem by increasing awareness of it and giving users more visibility and control when managing their NFTs.
Elliptic said it “identified at least three attackers who have purchased at least eight NFTs for much less than their market value within the past 12 hours.” The issue affects Bored Ape Yacht Club, Mutant Ape Yacht Club, Cool Cats and Cyberkongz NFTs.
DeFi developer Rotem Yakir released a detailed thread on Twitter explaining the OpenSea bug, writing that it “stems from the fact that previously you could re-list an NFT without canceling it (which you can’t now) and all the previous listing are not canceled on-chain. Previously, you could have re-list an NFT without canceling the previous list. Sometimes but not always, If you cancel your new listing, the old one will not appear on the UI but is still valid.”
According to OpenSea, the issue can arise any time a user moves an NFT to a different wallet without canceling active listings because the transaction is posted to the blockchain. The company added that it is in the process of changing its default listing duration from 6 months to 1 month so that if an NFT is transferred back into a wallet after 1 month, the listing will have expired.