CVE-2026-82407 Klever-Go: Validator registration accepts an unvalidated BLS public key → consensus liveness DoS
Attackers can submit invalid BLS keys to halt consensus, causing network downtime in Klever-Go blockchain nodes.
- 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-2026-82407?
CVE-2026-82407 is a high-severity denial of service 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, core/kapp/validators/validators.go Register and the runtime validator update path accept a submitted BLSPublicKey without curve, prime-order subgroup, or nonzero validation. When a validator with a malformed key becomes eligible and is selected into a consensus group, MultiSigner.Reset and the corresponding signature verification creation path cannot deserialize the group key and cancel the slot. This causes repeated missed rounds and throughput degradation, and a network whose consensus group equals the eligible validator set can halt completely. Genesis validation is not affected because that path already performs CheckPublicKeyValid. This issue is fixed in version 1.7.20.
Weakness: CWE-20
Which versions are affected by CVE-2026-82407?
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-2026-82407?
Upgrade github.com/klever-io/klever-go to 1.7.20 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-82407 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82407 exists.
Sources
Also known as GHSA-9wh6-9hq7-9688, GO-2026-6586.