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Zebra ScriptApplication · Zfnd

CVE-2026-41583

CRITICAL · 9.1 CVSS v3.1 Published 2026-05-08
Fix available
A fix is available. Upgrade to 4.3.1 / 5.0.2 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Zebra Zcash node failed to validate consensus rules for sighash hash types in V5 transactions after a refactoring, and incorrectly used 'canonical' hash type for V4 transactions instead of the raw value per spec. This allows Zebra nodes to accept blocks that zcashd nodes would reject, creating a dangerous consensus split between implementations.

MitigationUpgrade zebrad to version 4.3.1 or later and zebra-script to version 5.0.2 or later to patch the consensus validation issues.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Zebra ScriptApplication
Affected:< 5.0.2
ZebradApplication
Affected:< 4.3.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check zebrad binary version
    Run 'zebrad --version' or 'zebrad -V' to obtain the installed zebrad version number
    Affected if Version is less than 4.3.1 and the node processes V5 transactions
  2. Check zebra-script version
    Run 'zebra-script --version' or check the installed package version via cargo or system package manager
    Affected if Version is less than 5.0.2 and the node processes V5 transactions
  3. Verify node is validating V5 transactions
    Inspect node logs for V5 transaction processing, or check configuration for transaction version support settings
    Affected if Node actively processes V5 transactions (the consensus split only occurs when V5 transactions are validated)
  4. Compare against affected version ranges
    Compare the installed zebrad version to '< 4.3.1' and zebra-script version to '< 5.0.2' using the version numbers obtained above
    Affected if Either zebrad is below 4.3.1 OR zebra-script is below 5.0.2 while processing V5 transactions

You are affected if your zebrad version is below 4.3.1 or zebra-script version is below 5.0.2 AND your node is actively validating V5 transactions, as this creates a consensus split with zcashd nodes.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.3.1 / 5.0.2 or later
Fixed in 4.3.15.0.2
Interim mitigation

Upgrade zebrad to version 4.3.1 or later and zebra-script to version 5.0.2 or later to patch the consensus validation issues.

Recommended fix High confidence

zebrad >= 4.3.1 and zebra-script >= 5.0.2

  1. 1. Identify the currently installed zebra version by running 'zebrad --version' and 'zebra-script --version' (or checking your package manager)
  2. 2. For zebrad: Upgrade to version 4.3.1 or later by following your installation method (cargo, release binary, or package manager)
  3. 3. For zebra-script: Upgrade to version 5.0.2 or later using the same installation method used for zebrad
  4. 4. After upgrading, verify the new versions are correctly installed by checking 'zebrad --version' and 'zebra-script --version'
  5. 5. Review the zebra release notes for version 4.3.1 and zebra-script 5.0.2 to understand any configuration or operational changes required
  6. 6. Restart the zebra node services to load the updated binaries
  7. 7. Monitor the node after restart to ensure it syncs correctly and validates transactions with the proper sighash rules
Caveat This is a consensus-critical patch - nodes may experience chain reorganizations as invalid blocks are rejected; ensure proper backups and monitor for any sync issues after upgrade

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Zebra Script Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing6.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,200
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-41583 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data