Vulnerability in Zcashfoundation Zebra
CVE-2026-104422
The block sync download path in Zebra (zebrad) before 6.3.0 reads a block's height from its unvalidated coinbase scriptSig and drops blocks that appear too far behind the tip before consensus validation, without penalizing the supplying peer. Because V5 transaction IDs exclude the scriptSig, a malicious peer can repeatedly serve a canonical block whose coinbase claims height 1 while keeping the requested hash, delaying the node's discovery of the newest block.
Published .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/ZcashFoundation/zebra/security/advisories/GHSA-g95h-hw6g-pvgv (vendor-advisory)
- www.vulncheck.com/advisories/zebra-before-6.3.0-block-sync-denial-of-service-vi… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-104422?
- CVE-2026-104422 is a high-severity vulnerability in Zcashfoundation Zebra, classified under Insufficient Verification of Data Authenticity. CVSS score: 7.5/10. Published 2026-10-02.
- How severe is CVE-2026-104422?
- High severity. CVSS v3 base score is 7.5 out of 10.