What is CVE-2026-104430?

CVE-2026-104430 is a high-severity vulnerability in Zcashfoundation Zebra, classified under CWE-628. CVSS score: 7.5/10. Published 2026-10-02.

How severe is CVE-2026-104430?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Zcashfoundation Zebra

CVE-2026-104430

Zebra zebrad 4.5.0 and zebra-script 7.0.0 count P2SH redeem script signature operations in legacy mode rather than zcashd's accurate P2SH mode, overcounting CHECKMULTISIG preceded by OP_1 through OP_16 as 20 sigops and causing a consensus divergence. Remote attackers can broadcast P2SH spends using low-threshold multisig redeem scripts so that a block zcashd accepts exceeds Zebra's inflated MAX_BLOCK_SIGOPS count, causing Zebra nodes to reject it and stall off the chain.

Published 2026-10-02.

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

Zcashfoundation Zebra

Weakness classification (CWE)

CWE-628

References

GitHub Security Advisory (GHSA-2prc-cj5x-4443) (vendor-advisory)
VulnCheck Advisory: Zebra 4.5.0 Consensus Split via P2SH Sigop Overcount (third-party-advisory)

Frequently asked questions

What is CVE-2026-104430?: CVE-2026-104430 is a high-severity vulnerability in Zcashfoundation Zebra, classified under CWE-628. CVSS score: 7.5/10. Published 2026-10-02.
How severe is CVE-2026-104430?: High severity. CVSS v3 base score is 7.5 out of 10.