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CVE-2026-40880

Zebra: Cached Mempool Verification Bypasses Consensus Rules for Ahead-of-Tip Blocks

No known exploitation. EPSS puts it in the 37th percentile. Fixed versions are out.

CVSS 3.18.1HighEPSS percentile37th0.4% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFix4 products2 fixed builds listed below

Published Updated Sources: CVE.org, NVD

NVD CVE.org

What to do

Find your product and version, then upgrade to the build on the right.

  • ZcashFoundation zebradAffected: < 4.3.1Upgrade to: not statedStated by: CVE record
  • ZcashFoundation zebra-consensusAffected: < 5.0.2Upgrade to: not statedStated by: CVE record
  • Zfnd Zebra-consensusAffected: < 5.0.2Upgrade to: 5.0.2Stated by: NVD
  • Zfnd ZebradAffected: < 4.3.1Upgrade to: 4.3.1Stated by: NVD

Versions as the sources state them. Full version matrix after sign-in

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What it is

From the CVE record

ZEBRA is a Zcash node written entirely in Rust. Prior to zebrad version 4.3.1 and zebra-consensus version 5.0.2, a logic error in Zebra's transaction verification cache could allow a malicious miner to induce a consensus split. By carefully submitting a transaction that is valid for height H+1 but invalid for H+2 and then mining that transaction in a block at height H+2, a miner could cause vulnerable Zebra nodes to accept an invalid block, leading to a consensus split from the rest of the Zcash network. This vulnerability is fixed in zebrad version 4.3.1 and zebra-consensus version 5.0.2.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS37th
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

0.4% chance of exploitation activity in the next 30 days, which ranks it in the 37th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

4 events over 6 days, from the signal feeds we watch.

  1. Patch availablerecord updated
  2. Publishedweakness classified

Affected products

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

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

Scored 8.1 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required LowRequires basic user-level privileges
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality NoneNo confidentiality impact
  • Integrity HighTotal loss of integrity — attacker can modify any data in the component
  • Availability HighTotal denial of service — the component is completely unavailable

Weaknesses

Sources

References in the record

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We'll flag the next CVE, public exploit or patch for Zebra-consensus, not every advisory.