---
id: CVE-2026-104427
title: >-
  Zebra before 6.1.0 contains an incomplete cleanup vulnerability in the state
  write task that allows remote unauthenticated peers to stall node
  synchronization by poisoning parent_error_map
summary: >-
  Zebra before 6.1.0 contains an incomplete cleanup vulnerability in the state
  write task that allows remote unauthenticated peers to stall node
  synchronization by poisoning parent_error_map. Attackers can deliver a
  coinbase-malleated bloc…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-459
vendor: ZcashFoundation
product: zebra
affected:
  - zebra < 6.1.0
published: '2026-10-02'
updated: '2026-10-02'
sourceUpdated: '2026-10-02T12:17:13.030'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-104427'
references:
  - url: >-
      https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-8gxx-hc65-vv82
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/zebra-before-6.1.0-chain-stall-via-stale-parent-error-map-entry
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-02T12:17:44.332Z'
---

## Overview

Zebra before 6.1.0 contains an incomplete cleanup vulnerability in the state write task that allows remote unauthenticated peers to stall node synchronization by poisoning parent_error_map. Attackers can deliver a coinbase-malleated block sharing a canonical block's hash before it propagates, causing the next canonical block to be rejected and stalling the node for roughly 2,000 blocks.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.