What’s Vulnerable › Vulnerabilities

CVE-2026-58262: Klever-Go: PubKeysBitmap padding bits bypass the BLS signature quorum

• Severity: high (CVSS 7.1 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-07 · updated 2026-10-24
• Weakness: CWE-345

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.

Affected products

• klever-io klever-go: before 1.7.20

References

• https://github.com/klever-io/klever-go/commit/a11cb28e495e608d8034dbe83a91e89d0c68e0f7
• https://github.com/klever-io/klever-go/security/advisories/GHSA-f9h7-4mmq-vgcq

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