---
title: "CVE-2026-44498: Zebra's Block Validator Undercounts Coinbase and P2SH Sigops"
url: https://erroneo.us/security/cve/CVE-2026-44498/
description: "CVE-2026-44498 (zebrad (crates.io (Rust))): ZEBRA is a Zcash node written entirely in Rust. Prior to version 4.4.0, Zebra's block validator undercounts…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-05-08
date_modified: 2026-05-14
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-44498"
kev: false
cvss: 9.2
epss: 0.0038
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-44498: Zebra's Block Validator Undercounts Coinbase and P2SH Sigops

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.4% , percentile 31: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 31% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes zebrad (crates.io (Rust)) < 4.4.0, fixed in 4.4.0 . Check your lockfile, including transitive dependencies.

## What it is

ZEBRA is a Zcash node written entirely in Rust. Prior to version 4.4.0, Zebra's block validator undercounts transparent signature operations against the 20000-sigop block limit (MAXBLOCKSIGOPS), allowing it to accept blocks that zcashd rejects with bad-blk-sigops. A miner who produces such a block can split the network: Zebra nodes follow the offending chain while zcashd nodes do not. This issue has been patched in version 4.4.0.

## Affected packages

- crates.io (Rust) `zebrad` < 4.4.0 → fixed: 4.4.0

## Affected products (CVE record)

- ZcashFoundation zebra: < 4.4.0

## Severity

- GitHub_M CVSS 4.0: 9.2 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N`
- GitHub CVSS 4.0: 9.2 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.38% probability of exploitation activity in the next 30 days; percentile 31.

## Sources

- [GitHub Advisory GHSA-jv4h-j224-23cc](https://github.com/advisories/GHSA-jv4h-j224-23cc)
- [CVE.org record CVE-2026-44498](https://www.cve.org/CVERecord?id=CVE-2026-44498)
- [NVD entry CVE-2026-44498](https://nvd.nist.gov/vuln/detail/CVE-2026-44498)
- [github.com](https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-jv4h-j224-23cc)
- [github.com](https://github.com/ZcashFoundation/zebra/releases/tag/v4.4.0)

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Source page: https://erroneo.us/security/cve/CVE-2026-44498/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt