# CVE-2026-34202: Zebra node crash — V5 transaction hash panic (P2P reachable)

> Remote attackers can crash Zebra Zcash nodes by sending crafted V5 transactions, requiring an upgrade to patched versions.

- **Severity:** Critical 9.2 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 31 Mar 2026
- **Updated:** 31 Mar 2026
- **Also known as:** GHSA-qp6f-w4r3-h8wg

## What is CVE-2026-34202?

CVE-2026-34202 is a critical denial of service vulnerability in ZcashFoundation zebra, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

ZEBRA is a Zcash node written entirely in Rust. Prior to zebrad version 4.3.0 and zebra-chain version 6.0.1, a vulnerability in Zebra's transaction processing logic allows a remote, unauthenticated attacker to cause a Zebra node to panic (crash). This is triggered by sending a specially crafted V5 transaction that passes initial deserialization but fails during transaction ID calculation. This issue has been patched in zebrad version 4.3.0 and zebra-chain version 6.0.1.

Weakness: CWE-502 (Deserialization of Untrusted Data), CWE-94 (Improper Control of Generation of Code), CWE-1336 (Improper Neutralization of Special Elements Used in a Template Engine)

## Which versions are affected by CVE-2026-34202?

4 open source packages ship an affected version, including zebra-chain and zebrad. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `zebra-chain` | crates.io | All versions | 6.0.1 |
| `zebra-chain` | crates.io | All versions | 6.0.1 |
| `zebrad` | crates.io | All versions | 4.3.0 |
| `zebrad` | crates.io | All versions | 4.3.0 |

Products: Zfnd Zebra, Zfnd Zebra-Chain.

## How do I fix CVE-2026-34202?

Upgrade zebra-chain to 6.0.1 or later.

## Is CVE-2026-34202 being exploited?

There is no known exploitation of CVE-2026-34202 in the wild and no public exploit code.

## Other vulnerabilities in ZcashFoundation zebra

- [CVE-2026-34377](https://insights.sbomify.com/CVE-2026-34377/): Zebra has a Consensus Failure due to Improper Verification of V5 Transactions (high 8.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34202 and fix it if it is affected.

What it is: CVE-2026-34202 is a critical denial of service vulnerability in ZcashFoundation zebra, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-34202 in the wild and no public exploit code.

Affected packages and fixed versions:
- zebra-chain (crates.io): affected all versions; fixed in 6.0.1
- zebra-chain (crates.io): affected all versions; fixed in 6.0.1
- zebrad (crates.io): affected all versions; fixed in 4.3.0
- zebrad (crates.io): affected all versions; fixed in 4.3.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-34202/ (Markdown: https://insights.sbomify.com/CVE-2026-34202/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34202
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34202
- OSV: https://osv.dev/vulnerability/CVE-2026-34202

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34202/
Summaries are generated and may contain mistakes; the official description above is the record.