High severity · published Oct 2, 2026
CVE-2026-104430
Zebra 4.5.0 Consensus Split via P2SH Sigop Overcount
7.5
CVSS
0.4%
EPSS
No
On KEV
Description
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 35% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ZE
zebra · ZcashFoundation
4.5.0 before 4.5.1; 7.0.0 before 7.0.1 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-104430
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-104430
vendor-advisory
https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-2prc-cj5x-4443
third-party-advisory
https://www.vulncheck.com/advisories/zebra-4.5.0-consensus-split-via-p2sh-sigop-overcount
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