---
id: CVE-2026-104430
title: >-
  Zebra zebrad 4.5.0 and zebra-script 7.0.0 count P2SH redeem script signature
  operations in legacy mode rather than zcashd's accurate P2SH mode,
  overcounting CHECKMULTISIG preceded by OP_1 through OP_16 as 20 sigops and
  causing a consensu…
summary: >-
  Zebra zebrad 4.5.0 and zebra-script 7.0.0 count P2SH redeem script signature
  operations in legacy mode rather than zcashd's accurate P2SH mode,
  overcounting CHECKMULTISIG preceded by OP_1 through OP_16 as 20 sigops and
  causing a consensu…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-628
vendor: ZcashFoundation
product: zebra
affected:
  - zebra >= 4.5.0 < 4.5.1
  - zebra >= 7.0.0 < 7.0.1
published: '2026-10-02'
updated: '2026-10-02'
sourceUpdated: '2026-10-02T12:17:13.467'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-104430'
references:
  - url: >-
      https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-2prc-cj5x-4443
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/zebra-4.5.0-consensus-split-via-p2sh-sigop-overcount
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-02T12:17:44.333Z'
---

## Overview

Zebra zebrad 4.5.0 and zebra-script 7.0.0 count P2SH redeem script signature operations in legacy mode rather than zcashd's accurate P2SH mode, overcounting CHECKMULTISIG preceded by OP_1 through OP_16 as 20 sigops and causing a consensus divergence. Remote attackers can broadcast P2SH spends using low-threshold multisig redeem scripts so that a block zcashd accepts exceeds Zebra's inflated MAX_BLOCK_SIGOPS count, causing Zebra nodes to reject it and stall off the chain.

## Remediation

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