# CVE-2026-41583: ZEBRA: Consensus Divergence in Transparent Sighash Hash-Type Handling

> Zcash nodes may accept invalid blocks due to incorrect sighash validation, causing consensus splits with other nodes and potential network disruption.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:H/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 May 2026
- **Updated:** 8 May 2026
- **Also known as:** GHSA-8m29-fpq5-89jj

## What is CVE-2026-41583?

CVE-2026-41583 is a critical vulnerability in ZcashFoundation zebra, published on 8 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

ZEBRA is a Zcash node written entirely in Rust. Prior to zebrad version 4.3.1 and prior to zebra-script version 5.0.2, after a refactoring, Zebra failed to validate a consensus rule that restricted the possible values of sighash hash types for V5 transactions which were enabled in the NU5 network upgrade. Zebra nodes could thus accept and eventually mine a block that would be considered invalid by zcashd nodes, creating a consensus split between Zebra and zcashd nodes. In a similar vein, for V4 transactions, Zebra mistakenly used the "canonical" hash type when computing the sighash while zcashd (correctly per the spec) uses the raw value, which could also crate a consensus split. This issue has been patched in zebrad version 4.3.1 and zebra-script version 5.0.2.

Weakness: CWE-573 (Improper Following of Specification by Caller)

## Which versions are affected by CVE-2026-41583?

4 open source packages ship an affected version, including zebra-script and zebrad. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `zebra-script` | crates.io | All versions | 5.0.2 |
| `zebra-script` | crates.io | All versions | 5.0.2 |
| `zebrad` | crates.io | All versions | 4.3.1 |
| `zebrad` | crates.io | All versions | 4.3.1 |

Products: Zfnd Zebra-Script, Zfnd Zebrad.

## How do I fix CVE-2026-41583?

Upgrade zebra-script to 5.0.2 or later.

## Is CVE-2026-41583 being exploited?

There is no known exploitation of CVE-2026-41583 in the wild and no public exploit code.

## Other vulnerabilities in ZcashFoundation zebra

- [CVE-2026-44497](https://insights.sbomify.com/CVE-2026-44497/): ZEBRA: Consensus Divergence in Transparent Sighash Hash-Type Handling due to Stale Buffer (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-41583 and fix it if it is affected.

What it is: CVE-2026-41583 is a critical vulnerability in ZcashFoundation zebra, published on 8 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-41583 in the wild and no public exploit code.

Affected packages and fixed versions:
- zebra-script (crates.io): affected all versions; fixed in 5.0.2
- zebra-script (crates.io): affected all versions; fixed in 5.0.2
- zebrad (crates.io): affected all versions; fixed in 4.3.1
- zebrad (crates.io): affected all versions; fixed in 4.3.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-41583/ (Markdown: https://insights.sbomify.com/CVE-2026-41583/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-41583
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-41583
- OSV: https://osv.dev/vulnerability/CVE-2026-41583

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-41583/
Summaries are generated and may contain mistakes; the official description above is the record.