---
id: CVE-2026-123556
title: Zebra 4.5.0 before 7.0.0 Honest Peer Ban via Mempool Lock-Time Scoring
summary: >-
  ZcashFoundation Zebra from 4.5.0 before 7.0.0 contains a protection mechanism
  failure that bans honest peers by scoring mempool lock-time rejections at the
  ban threshold. Attackers can broadcast transactions locked until the current
  heig…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'
cvssSource: cna
cwe:
  - CWE-693
vendor: ZcashFoundation
product: zebra
affected:
  - zebra >= 4.5.0 < 7.0.0
published: '2026-11-08'
updated: '2026-11-08'
sourceUpdated: '2026-11-08T01:37:58.283Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-123556'
references:
  - url: >-
      https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-5h3r-fpmj-483w
    label: GitHub Security Advisory (GHSA-5h3r-fpmj-483w)
  - url: >-
      https://www.vulncheck.com/advisories/zebra-4.5.0-before-7.0.0-honest-peer-ban-via-mempool-lock-time-scoring
    label: >-
      VulnCheck Advisory: Zebra 4.5.0 before 7.0.0 Honest Peer Ban via Mempool
      Lock-Time Scoring
tags:
  - cve.org
ingestedAt: '2026-11-08T02:43:18.666Z'
---

## Overview

ZcashFoundation Zebra from 4.5.0 before 7.0.0 contains a protection mechanism failure that bans honest peers by scoring mempool lock-time rejections at the ban threshold. Attackers can broadcast transactions locked until the current height right after each block, causing lagging nodes to ban honest relaying peers for 24 hours or until restart.

## Affected

- `zebra >= 4.5.0 < 7.0.0`

## Remediation

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