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

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.9%, percentile 60: FIRST’s model estimates a 0.9% chance of exploitation activity in the next 30 days, higher than 60% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes zebrad (crates.io (Rust)) < 4.3.0, fixed in 4.3.0; zebra-chain (crates.io (Rust)) < 6.0.1, fixed in 6.0.1. Check your lockfile, including transitive dependencies.

What it is

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.

From the GitHub advisory

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Remote Denial of Service via Crafted V5 Transactions

Summary 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.

Severity Critical - This is a Remote Denial of Service (DoS) that requires no authentication and can be triggered by a single network message.

Affected Versions All Zebra versions supporting V5 transactions (Network Upgrade 5 and later) prior to version 4.3.0.

Weakness type: CWE-1336, CWE-94.

Product: zebrad (crates.io (Rust)) · Assigned by: GitHub_M · Published: 2026-03-31

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Attack requirements: none
• Privileges required: none (no login)
• User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable yes, technical impact partial.
• FIRST EPSS (model of 2026-10-21): 0.93% probability of exploitation activity in the next 30 days; percentile 60.

Timeline

• 2026-03-27 — GitHub-reviewed advisory GHSA-qp6f-w4r3-h8wg published (critical)
• 2026-03-31 — CVE record last updated
• 2026-03-31 — CVE record published by GitHub_M

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-qp6f-w4r3-h8wg github.com
2. CVE.org record CVE-2026-34202 cve.org
3. NVD entry CVE-2026-34202 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. zfnd.org zfnd.org

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