---
id: CVE-2026-104432
title: >-
  Zebra before 6.3.0 contains an improper exceptional condition check in
  ChainSync::obtain_tips that discards valid one-hash FindBlocks responses,
  falsely reporting close-to-tip status
summary: >-
  Zebra before 6.3.0 contains an improper exceptional condition check in
  ChainSync::obtain_tips that discards valid one-hash FindBlocks responses,
  falsely reporting close-to-tip status. Peers returning only the next block
  hash cause a zero…
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'
cwe:
  - CWE-754
vendor: ZcashFoundation
product: zebra
affected:
  - zebra < 6.3.0
published: '2026-10-02'
updated: '2026-10-02'
sourceUpdated: '2026-10-02T12:17:13.763'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-104432'
references:
  - url: >-
      https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-h8m8-844p-v3m9
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/zebra-before-6.3.0-false-readiness-via-discarded-one-hash-findblocks-response
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-02T12:17:44.333Z'
---

## Overview

Zebra before 6.3.0 contains an improper exceptional condition check in ChainSync::obtain_tips that discards valid one-hash FindBlocks responses, falsely reporting close-to-tip status. Peers returning only the next block hash cause a zero-length sync sample, making the /ready endpoint return 200 OK while the node remains behind the tip.

## Remediation

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