{"id":"CVE-2026-52735","revision":"166c52f60f4c4b7ea7ee25accc011612","records":[{"revision":"166c52f60f4c4b7ea7ee25accc011612","observedAt":"2026-10-25T13:17:10.707+00:00","statement":{"source":"nvd","id":"CVE-2026-52735","aliases":[],"title":"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.…","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.","state":0,"publishedAt":"2026-08-18T20:17:17.227+00:00","modifiedAt":"2026-10-22T22:10:00.25+00:00","affected":[],"metrics":[{"system":"CVSS 4.0 · security-advisories@github.com · Secondary","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: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","score":9.3,"severity":"CRITICAL"}],"references":["https://github.com/ZcashFoundation/zebra/commit/1440b43ca7df59aca948090d45117557b217a6cd","https://github.com/ZcashFoundation/zebra/releases/tag/v4.5.0","https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-gf9r-m956-97qx"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-52735","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Deferred","weaknesses":["CWE-684"],"productCriteria":[],"sourceDates":{"published":"2026-08-18T20:17:17.227","lastModified":"2026-10-22T22:10:00.250"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-52735","identifiers":["CVE-2026-52735"]},"retained":false,"historicalAffected":[]}],"coverage":[]}