---
id: CVE-2026-104426
title: >-
  Zebra before 6.1.0 contains an inefficient algorithmic complexity
  vulnerability in remaining_transaction_value that clones the entire
  block-level spent-UTXO map per transaction during contextual verification
summary: >-
  Zebra before 6.1.0 contains an inefficient algorithmic complexity
  vulnerability in remaining_transaction_value that clones the entire
  block-level spent-UTXO map per transaction during contextual verification.
  Attackers can mine or seed t…
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-407
vendor: ZcashFoundation
product: zebra
affected:
  - zebra < 6.1.0
published: '2026-10-02'
updated: '2026-10-02'
sourceUpdated: '2026-10-02T12:17:12.887'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-104426'
references:
  - url: >-
      https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-4g24-549m-hp75
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/zebra-before-6.1.0-quadratic-complexity-dos-via-block-transparent-value-check
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-02T12:17:44.331Z'
---

## Overview

Zebra before 6.1.0 contains an inefficient algorithmic complexity vulnerability in remaining_transaction_value that clones the entire block-level spent-UTXO map per transaction during contextual verification. Attackers can mine or seed the mempool with roughly 26,000 minimal single-input transactions in one block, stalling every validating node for over 52 seconds.

## Remediation

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