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.

CVSS 4.0

8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

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

EPSS

0.4% chance of exploitation in the next 30 days; higher than 34% of CVEs (scores of 2026-10-25)

CWE

CWE-628

Published

2026-10-02

Modified

2026-10-02

Record from

the NVD, synced 2026-10-19

References

• https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-2prc-cj5x-4443
• https://www.vulncheck.com/advisories/zebra-4.5.0-consensus-split-via-p2sh-sigop-overcount

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