CVE-2026-58262 Klever-Go: PubKeysBitmap padding bits bypass the BLS signature quorum
A malicious block producer can bypass BLS signature quorum checks by exploiting padding bits, compromising consensus safety in Klever-Go nodes.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-58262?
CVE-2026-58262 is a high-severity vulnerability in klever-io klever-go, published on 7 Aug 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, header signature verification counts the unused padding bits of the PubKeysBitmap toward the two-thirds validator quorum. These padding bits do not correspond to any validator and are ignored by the actual BLS aggregate-signature check, so a malicious or compromised block producer can set them to reach the required quorum while gathering fewer genuine validator signatures than the protocol demands. As a result, nodes that import or intercept the header accept it as correctly signed without a real two-thirds quorum, weakening consensus safety and undermining finality. This issue is fixed in version 1.7.20.
Which versions are affected by CVE-2026-58262?
How do I fix CVE-2026-58262?
No fix has been published for CVE-2026-58262 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-58262 being exploited?
There is no known exploitation of CVE-2026-58262 in the wild and no public exploit code.
Sources
Also known as GHSA-f9h7-4mmq-vgcq.