What’s Vulnerable › Vulnerabilities

CVE-2026-34377: Zebra has a Consensus Failure due to Improper Verification of V5 Transactions

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-03-31 · updated 2026-07-24
• Weakness: CWE-347

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.

Affected products

• Zfnd Zebra: before 4.3.0 — fixed in 4.3.0
• ZcashFoundation zebra-consensus: before 5.0.1 — fixed in 5.0.1

How to fix

Upgrade to a fixed version: Zfnd Zebra 4.3.0; ZcashFoundation zebra-consensus 5.0.1. Check the vendor advisory for mitigations.

References

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

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