CVE-2026-104430 PUBLISHED

Zebra 4.5.0 Consensus Split via P2SH Sigop Overcount

Assigner: VulnCheck
Reserved: 02.10.2026 Published: 02.10.2026 Updated: 02.10.2026

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: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 Score: 8.7

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	None	Integrity	None
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

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

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	None
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	ZcashFoundation
Product	zebra
Versions	Default: unaffected affected from 4.5.0 to 4.5.1 (excl.) Version 4.5.1 is unaffected

Vendor	ZcashFoundation
Product	zebra
Versions	Default: unaffected affected from 7.0.0 to 7.0.1 (excl.) Version 7.0.1 is unaffected

CVE-2026-104430 PUBLISHED

Zebra 4.5.0 Consensus Split via P2SH Sigop Overcount

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