CyberRota Analysis
AI-GeneratedZebra, a Zcash node implementation, is vulnerable to a consensus issue that allows attackers to broadcast P2SH transactions that are accepted by Zebra but rejected by the zcashd reference implementation, potentially leading to a network split. This flaw arises from an incorrect handling of signature-operation counting in the presence of disabled opcodes, which could compromise network integrity and availability. Operators of Zcash nodes, particularly those using Zebra versions prior to 4.5.0, should prioritize upgrading to mitigate this critical risk.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
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Original NVD 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.