CVE-2026-34202
A remote attacker can crash a ZEBRA Zcash node by sending a specially crafted transaction. The crash occurs during transaction ID calculation after deserialization. The issue is fixed in newer versions.
An official fix is available, so this entry is kept for 30 days and then removed automatically.
Who is affected
ZEBRA node (zfnd zebra) and zebra-chain (zfnd zebra-chain) versions prior to zebrad 4.3.0 and zebra-chain 6.0.1. Users running these older nodes are affected.
Real-world impact
An attacker can cause a denial‑of‑service by crashing the node, disrupting its participation in the Zcash network and potentially affecting other participants.
Why this severity
The CVSS score of 9.2 reflects the high impact on availability (the node crashes) combined with low attack complexity and no authentication required. The vulnerability is critical because it can be exploited remotely with minimal effort.
What to do about it
- 01Upgrade zebrad to version 4.3.0 or later.
- 02Upgrade zebra-chain to version 6.0.1 or later.
- 03Restart the node to apply the update.
NVD-referenced vendor advisory
Timeline
- Mar 31, 2026 · Mar 31, 2026PublishedDisclosed and added to the National Vulnerability Database.
- Jul 24, 2026 · 12d agoAdvisory updatedThe NVD record was last revised.
- Jul 26, 2026 · 10d agoOfficial fix availableA vendor patch or mitigation now exists — see the remediation steps above.
How it’s attacked
References & advisories
- github.com/ZcashFoundation/zebra/relea…release notes
- github.com/ZcashFoundation/zebra/secur…vendor advisory
- zfnd.org/zebra-4-3-0-critical-securi…vendor advisory