{"apiVersion":"1.0","identifier":"CVE-2026-52735","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.","publishedAt":"2026-08-18T20:17:17","lastModifiedAt":"2026-08-18T20:17:17","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-52735","cvssScore":9.3,"cvssVector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","epssProbability":0.00291,"riskScore":0.95,"affectedProduct":"Zebra","affectedVersions":"<4.5.0","vulnerabilityType":"Other","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-52735","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-52735","en":"https://www.redsauce.net/en/cves/CVE-2026-52735","fr":"https://www.redsauce.net/fr/cves/CVE-2026-52735","pt":"https://www.redsauce.net/pt/cves/CVE-2026-52735","de":"https://www.redsauce.net/de/cves/CVE-2026-52735","sk":"https://www.redsauce.net/sk/cves/CVE-2026-52735","el":"https://www.redsauce.net/el/cves/CVE-2026-52735"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-52735"}}