CVE-2026-58262: Klever-Io Klever-Go

High severity, CVSS 7.1. EPSS: 0.2% chance of exploitation in the next 30 days.

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 (fixed in 1.7.20)

Published 2026-08-07. Last modified 2026-09-09.