CVE-2026-82406 Klever-Go: Zombie-order theft: `Buy` missing `IsClaimed` guard in native marketplace
Attackers can exploit missing state checks in the marketplace to steal funds or NFTs by bypassing claimed order restrictions.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-82406?
CVE-2026-82406 is a high-severity vulnerability in klever-io klever-go, published on 23 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.20, the native marketplace function core/kapp/market/market.go Buy does not check IsClaimed before accepting a bid. A seller can use the Claim seller-accept branch to settle a resting-bid auction while leaving the claimed order loadable with a future EndTime and stale CurrentBid and CurrentBidder values. A later bidder can submit a higher bid, be debited, and cause the previous bidder to receive a refund even though the NFT has already been delivered. Because Claim and CancelOrder reject the later bidder when IsClaimed is true, the later bidder cannot obtain the NFT or recover the funds. This issue is fixed in version 1.7.20.
Weakness: CWE-841
Which versions are affected by CVE-2026-82406?
3 open source packages ship an affected version, including github.com/klever-io/klever-go.
| Package | Affected | Fixed in |
|---|---|---|
github.com/klever-io/klever-go Go | All versions | 1.7.20 |
github.com/klever-io/klever-go Go | All versions | 1.7.20 |
github.com/klever-io/klever-go Go | All versions | 1.7.20 |
How do I fix CVE-2026-82406?
Upgrade github.com/klever-io/klever-go to 1.7.20 or later.
Is CVE-2026-82406 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82406 exists.
Sources
Also known as GHSA-26r5-4mm2-px5c, GO-2026-6584.