NFTs
Cancel your old listings on OpenSea or risk having your precious NFTs taken away
Over $1 million worth of NFTs were purchased at steep discounts due to a listing bug.
A ‘bug’ discovered a few weeks ago on OpenSea, the leading NFT marketplace, able Over $1 million worth of non-fungible tokens will be purchased at steep discounts on January 24.
A user who passes by jpegdegenamor managed to acquire two Bored Apes, two Mutant Apes, a Cyberkongz Genesis and a Cool Cat for a total of 57.31 ETH (US$ 137 thousand).
Quite a feat, considering the cheapest Bored Monkey NFT currently costs 93 ETH ($223,000).
All six NFTs were later sold for 390 ETH ($936,000), netting a profit of over $700,000.
That’s how it happened.
Listing an NFT for sale on OpenSea is free.
Once a user approves a certain NFT collection for sale with a token approval, listings only require a signature. However, canceling a listing requires an on-chain transaction that costs gas fees.
To avoid paying the cancellation fee, intrepid NFT traders came up with a workaround of transferring the NFT to another wallet. Since the NFT was no longer in the original wallet, all listings for it would be invalidated and automatically removed from the OpenSea website.
OpenSea stores listings and offers in an off-chain database to save users gas fees. This is why listings and offers only require a subscription.
When an NFT with active listings is transferred, the listings disappear from the OpenSea website but remain in the database. These listings remain active until their set expiration dates and can be accessed through the OpenSea API. Rarible, a competing NFT marketplace, is another listing data source.
If the NFT is later transferred back to the original wallet, the old listings can be used to purchase the item.
And that’s exactly what happened, as we can see in the case of CyberKongz #155.
Image by Rotem Yakir, who posted a Twitter Thread analyzing the issue.
It looks like OpenSea has removed jpegdegenlove’s account page.
Cancel Old Listings
If you are active in the NFT market, you may want to review your old listings and cancel any NFTs you still have. Rare is a convenient place to check.
Stay safe out there!