CVE-2026-34202

HighRCE

Published: 31 March 2026

Published

31 March 2026

Modified

07 April 2026

KEV Added

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Patch

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CVSS Score 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Score 0.0015 35.5th percentile

Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-34202 is a high-severity Code Injection (CWE-94) vulnerability in Zfnd Zebra. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 35.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-11 (Error Handling).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190) and 1 other technique. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-2 Flaw Remediation good match

prevent

Requires timely identification, reporting, and correction of the specific flaw in Zebra's transaction processing logic, enabling patching to versions 4.3.0 and 6.0.1 as recommended.

SI-11 Error Handling good match

prevent

Mandates secure error handling to prevent panics and crashes during transaction ID calculation failures from specially crafted V5 transactions.

SI-10 Information Input Validation good match

prevent

Enforces validation of incoming V5 transactions at network interfaces to block malformed inputs that pass deserialization but trigger ID calculation failures.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1499.004 Application or System Exploitation Impact

Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.

attack.mitre.org →

Why these techniques?

Vulnerability enables remote exploitation of public-facing Zebra node (T1190) via crafted transaction input, directly causing application crash and denial of service (T1499.004).

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD 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.

Deeper analysisAI

CVE-2026-34202 is a vulnerability in Zebra, a Zcash node implementation written entirely in Rust, affecting zebrad versions prior to 4.3.0 and zebra-chain versions prior to 6.0.1. The flaw resides in Zebra's transaction processing logic, where a specially crafted V5 transaction can pass initial deserialization but trigger a failure during transaction ID calculation, causing the node to panic and crash. It is associated with CWEs-94 (code injection), CWE-1336, and CWE-502 (deserialization of untrusted data), and carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

A remote, unauthenticated attacker can exploit this vulnerability by sending the malicious V5 transaction to a vulnerable Zebra node over the network. Successful exploitation results in a denial-of-service condition, as the node crashes due to the panic, disrupting its availability for transaction validation and blockchain synchronization without impacting confidentiality or integrity.

The issue has been patched in zebrad version 4.3.0 and zebra-chain version 6.0.1. Security advisories recommend immediate upgrading to these fixed versions to mitigate the risk. Additional details are available in the GitHub release notes (https://github.com/ZcashFoundation/zebra/releases/tag/v4.3.0), the security advisory (https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-qp6f-w4r3-h8wg), and the Zcash Foundation announcement (https://zfnd.org/zebra-4-3-0-critical-security-fixes-zip-235-support-and-performance-improvements).