CVE-2026-34377: Zfnd Zebra-consensus vulnerability (CVSS 8.1)

Description

ZEBRA is a Zcash node written entirely in Rust. Prior to zebrad version 4.3.0 and zebra-consensus version 5.0.1, a logic error in Zebra's transaction verification cache could allow a malicious miner to induce a consensus split. By matching a valid transaction's txid while providing invalid authorization data, 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 would not allow invalid transactions to be accepted but could result in a consensus split between vulnerable Zebra nodes and invulnerable Zebra and Zcashd nodes. This issue has been patched in zebrad version 4.3.0 and zebra-consensus version 5.0.1.

CVSS 3.1 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredLow

User interactionNone

ScopeUnchanged

ConfidentialityNone

IntegrityHigh

AvailabilityHigh

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

Affected products

Zfnd Zebra-consensus< 5.0.1

Zfnd Zebra< 4.3.0

Remediation

Fixed in

Zfnd Zebra-consensus≥ 5.0.1

Zfnd Zebra≥ 4.3.0

Patch & vendor advisories

References

https://github.com/ZcashFoundation/zebra/releases/tag/v4.3.0Release Notes
https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-3vmh-33xr-9cqhExploitVendor Advisory
https://zfnd.org/zebra-4-3-0-critical-security-fixes-zip-235-support-and-performance-improvementsVendor Advisory

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2026-34377 being actively exploited?

CVE-2026-34377 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.38%.

How severe is CVE-2026-34377?

CVE-2026-34377 has a CVSS 3.1 base score of 8.1, rated high. EPSS estimates a 0.38% probability of exploitation.

Which products are affected by CVE-2026-34377?

Affected products include Zfnd Zebra-consensus, Zfnd Zebra.

How do I fix CVE-2026-34377?

Upgrade affected software to a fixed version, for example Zfnd Zebra-consensus 5.0.1, Zfnd Zebra 4.3.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-34377 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

See how prioritisation works Book a demo