Vulnerability in Zcashfoundation Zebra
CVE-2026-104423
Zebra (zebrad) before 6.2.1 contains an asymmetric resource consumption vulnerability that allows unauthenticated peers to stall block verification by pushing V6 mempool transactions with invalid Halo2 proofs. Attackers can flood the shared unprioritized Halo2 verification queue with zero-fee transactions carrying zero-filled Orchard and Ironwood proofs, causing nodes to fall behind the chain tip.
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 Security Advisory (GHSA-2p4c-3q4q-p463) (vendor-advisory)
- VulnCheck Advisory: Zebra before 6.2.1 Denial of Service via Uncapped V6 Shielded Proof Verification (third-party-advisory)
Frequently asked questions
- What is CVE-2026-104423?
- CVE-2026-104423 is a high-severity vulnerability in Zcashfoundation Zebra, classified under Asymmetric Resource Consumption (Amplification). CVSS score: 7.5/10. Published 2026-10-02.
- How severe is CVE-2026-104423?
- High severity. CVSS v3 base score is 7.5 out of 10.