---
id: CVE-2026-123557
title: Zebra zebrad before 7.0.0 Reachable Assertion DoS via Peer Disconnection
summary: >-
  ZcashFoundation Zebra zebrad before 7.0.0 contains a reachable assertion race
  condition that allows unauthenticated remote peers to abort the node by
  triggering disconnection during a blocked outbound send. Malicious peers can
  return emp…
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'
cvssSource: cna
cwe:
  - CWE-617
vendor: ZcashFoundation
product: zebra
affected:
  - zebra < 7.0.0
published: '2026-11-08'
updated: '2026-11-08'
sourceUpdated: '2026-11-08T01:37:58.967Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-123557'
references:
  - url: >-
      https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-6v36-c42v-v98p
    label: GitHub Security Advisory (GHSA-6v36-c42v-v98p)
  - url: >-
      https://www.vulncheck.com/advisories/zebra-zebrad-before-7.0.0-reachable-assertion-dos-via-peer-disconnection
    label: >-
      VulnCheck Advisory: Zebra zebrad before 7.0.0 Reachable Assertion DoS via
      Peer Disconnection
tags:
  - cve.org
ingestedAt: '2026-11-08T02:43:18.665Z'
---

## Overview

ZcashFoundation Zebra zebrad before 7.0.0 contains a reachable assertion race condition that allows unauthenticated remote peers to abort the node by triggering disconnection during a blocked outbound send. Malicious peers can return empty FindBlocks or FindHeaders replies and stop reading their socket, dropping an unresolved MustUseClientResponseSender and terminating syncing nodes.

## Affected

- `zebra < 7.0.0`

## Remediation

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