---
id: "CVE-2026-82407"
kind: "vulnerability"
aliases: ["CVE-2026-82407", "GHSA-9wh6-9hq7-9688", "GO-2026-6586"]
title: "Klever-Go: Validator registration accepts an unvalidated BLS public key \u2192 consensus liveness DoS in github.com/klever-io/klever-go"
severity: "high"
cvss: 7.0
epss: 0.00434
exploited: false
status: "open"
category: "package"
products: [{"name": "github.com/klever-io/klever-go", "fixed": ["1.7.20"], "affected": "< 1.7.20", "ecosystem": "go"}]
ecosystems: ["go"]
tags: ["blockchain-node", "go", "klever-go", "package", "validators"]
not_affected_if: ["genesis-only-validators", "version-1.7.20-or-later"]
published_at: "2026-09-23T20:17:16+00:00"
first_seen_at: "2026-10-23T19:13:08+00:00"
updated_at: "2026-10-23T19:56:24+00:00"
sources: [{"source": "govuln", "url": "https://pkg.go.dev/vuln/GO-2026-6586", "first_seen_at": "2026-10-23T19:13:08+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-82407", "first_seen_at": "2026-10-23T19:13:43+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-82407", "first_seen_at": "2026-10-23T19:35:23+00:00"}]
---

# Klever-Go: Validator registration accepts an unvalidated BLS public key → consensus liveness DoS in github.com/klever-io/klever-go

Klever-Go, the Go implementation of the Klever blockchain node, accepts validator registrations with a BLS public key that is never checked for curve or subgroup validity. A malformed key lets anyone who registers a validator cause repeated missed consensus rounds, and in some configurations a full network halt.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- go:github.com/klever-io/klever-go affected < 1.7.20 fixed 1.7.20

## How to check

Run go list -m github.com/klever-io/klever-go in the node module and check whether the version is below 1.7.20.

## Fix

Upgrade github.com/klever-io/klever-go to 1.7.20 or later.

## Timeline

- 2026-10-23T19:13:08+00:00 govuln https://pkg.go.dev/vuln/GO-2026-6586
- 2026-10-23T19:13:43+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-82407
- 2026-10-23T19:35:23+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-82407

## From the sources

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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_