critical

CVE-2026-52735

zebrad has consensus divergence via P2SH sigop undercount in pure-Rust disabled-opcode parser

Published 18 Aug 2026Modified 22 Oct 2026CWE 684

In the Trivy database since at least 24 Oct 2026, 07:11 UTCWhen it arrived before that build is not recorded.

Severity by source

GHSA9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:H

Trivy's own label is CRITICAL. Rated critical by GHSA.

Description

ZEBRA is a Zcash node written entirely in Rust. Prior to 4.5.0, Zebra can accept a block that zcashd rejects because the P2SH signature-operation counter undercounts redeem scripts containing a disabled opcode followed by signature opcodes. In zebra-script/src/lib.rs, p2sh_input_sigop_count used the pure-Rust script::Code::sig_op_count path, whose try_fold parser stops at disabled opcodes such as OP_CODESEPARATOR and returns only the partial count accumulated before the error. The zcashd reference implementation continues static signature-operation counting through disabled opcodes, so an attacker can broadcast P2SH spends that Zebra counts below MAX_BLOCK_SIGOPS while zcashd counts above the 20,000-operation limit. If a Zebra miner includes those transactions, Zebra validators accept the block while zcashd validators reject it, creating a consensus chain split that affects network integrity and availability without requiring the attacker to produce a block. This issue is fixed in version 4.5.0.

Affected packages and fixed versions

Source	Package	Fixed in
cargo::GitHub Security Advisory Rust	zebra-script, zebrad	7.0.0 and 1 more

Show all 2 entries from 1 source

Source	Package	Fixed in
cargo::GitHub Security Advisory Rust	zebra-script	7.0.0
cargo::GitHub Security Advisory Rust	zebrad	4.5.0

References

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