# Zebra has a Consensus Failure due to Improper Verification of V5 Transactions

Advisory record · `GHSA-3vmh-33xr-9cqh`

- **Identifiers:** `GHSA-3vmh-33xr-9cqh` · `CVE-2026-34377`
- **State:** Confirmed
- **Severity:** CVSS 8.4 High
- **Critical:** No
- **Weakness (CWE):** [CWE-347](https://cwe.mitre.org/data/definitions/347.html)
- **Tags:** [Weak cryptography or TLS](https://agentprime.io/advisories/tag/weak-crypto.md)
- **Published:** 30 Mar 2026
- **Updated:** 31 Mar 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 30 Mar 2026, 19:13 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `zebrad` (crates.io): affected `<4.3.0`; fixed in `4.3.0`
- `zebra-consensus` (crates.io): affected `<5.0.1`; fixed in `5.0.1`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Zebra nodes running versions before 4.3.0 (the zebrad package, and zebra-consensus before 5.0.1) can accept a block containing a V5 transaction whose authorization data was altered, because the verification cache matches only on the transaction id. A malicious miner who sees a valid transaction in a node's mempool could craft such a block and cause that node to split from the rest of the Zcash network. Upgrade zebrad to 4.3.0 or later and zebra-consensus to 5.0.1 or later; the source lists no workarounds.

Written 8 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 8.4 High, CVSS 4.0: `CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:H/SC:N/SI:H/SA:H`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0026, the 17th percentile, on 13 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 15:18 UTC: First seen by agentprime
- 31 Oct 2026, 15:18 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-3vmh-33xr-9cqh)

## Sources

- [GitHub Advisory Database: GHSA-3vmh-33xr-9cqh](https://github.com/advisories/GHSA-3vmh-33xr-9cqh)
- [OSV: GHSA-3vmh-33xr-9cqh](https://osv.dev/vulnerability/GHSA-3vmh-33xr-9cqh)
- <https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-3vmh-33xr-9cqh>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-34377>
- <https://github.com/ZcashFoundation/zebra>
- <https://github.com/ZcashFoundation/zebra/releases/tag/v4.3.0>
- <https://zfnd.org/zebra-4-3-0-critical-security-fixes-zip-235-support-and-performance-improvements>
- <https://zips.z.cash/zip-0244>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-3vmh-33xr-9cqh>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-3vmh-33xr-9cqh/>. Everything for agents: <https://agentprime.io/llms.txt>.