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Critical · 9.3 CVE-2026-41583 EUVD-2026-28653GHSA-8m29-fpq5-89jj

ZEBRA: Consensus Divergence in Transparent Sighash Hash-Type Handling

Published May 8, 2026 · Updated May 8, 2026 · Assigned by GitHub_M

Description

ZEBRA is a Zcash node written entirely in Rust. Prior to zebrad version 4.3.1 and prior to zebra-script version 5.0.2, after a refactoring, Zebra failed to validate a consensus rule that restricted the possible values of sighash hash types for V5 transactions which were enabled in the NU5 network upgrade. Zebra nodes could thus accept and eventually mine a block that would be considered invalid by zcashd nodes, creating a consensus split between Zebra and zcashd nodes. In a similar vein, for V4 transactions, Zebra mistakenly used the "canonical" hash type when computing the sighash while zcashd (correctly per the spec) uses the raw value, which could also crate a consensus split. This issue has been patched in zebrad version 4.3.1 and zebra-script version 5.0.2.

Affected products

VendorProductAffectedFixed
ZcashFoundation zebra zebrad < 4.3.1, zebra-script < 5.0.2 —

Affected packages

EcosystemPackageAffectedFixedRecord
crates.io zebra-script < 5.0.2 5.0.2 GHSA-8m29-fpq5-89jj
crates.io zebrad < 4.3.1 4.3.1 GHSA-8m29-fpq5-89jj

References