CVE-2026-44498

ZEBRA: Block Validator Undercounts Coinbase and P2SH Sigops

Published May 8, 2026 CVSS 4.0 · 9.2 Critical EPSS < 1% KEV · Not listed
Description
ZEBRA is a Zcash node written entirely in Rust. Prior to version 4.4.0, Zebra's block validator undercounts transparent signature operations against the 20000-sigop block limit (MAX_BLOCK_SIGOPS), allowing it to accept blocks that zcashd rejects with bad-blk-sigops. A miner who produces such a block can split the network: Zebra nodes follow the offending chain while zcashd nodes do not. This issue has been patched in version 4.4.0.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-jv4h-j224-23cc Zebra's Block Validator Undercounts Coinbase and P2SH Sigops
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Zcashfoundation
Zcashfoundation zebra
Vendors & Products Zcashfoundation
Zcashfoundation zebra
Type Values Removed Values Added
First Time appeared Zfnd
Zfnd zebrad
CPEs cpe:2.3:a:zfnd:zebrad:*:*:*:*:*:rust:*:*
Vendors & Products Zfnd
Zfnd zebrad
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'}

Type Values Removed Values Added
Description ZEBRA is a Zcash node written entirely in Rust. Prior to version 4.4.0, Zebra's block validator undercounts transparent signature operations against the 20000-sigop block limit (MAX_BLOCK_SIGOPS), allowing it to accept blocks that zcashd rejects with bad-blk-sigops. A miner who produces such a block can split the network: Zebra nodes follow the offending chain while zcashd nodes do not. This issue has been patched in version 4.4.0.
Title ZEBRA: Block Validator Undercounts Coinbase and P2SH Sigops
Weaknesses CWE-682
References
Metrics cvssV4_0

{'score': 9.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 14, 2026, 9:32 PM
Reserved
May 6, 2026, 6:28 PM
Status
Analyzed
Published
May 8, 2026, 3:17 PM
Modified
Jun 17, 2026, 10:50 AM