CVE-2026-52735
- Source
- https://cve.org/CVERecord?id=CVE-2026-52735
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-52735.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-52735
- Aliases
- Published
- 2026-08-18T19:23:10.705Z
- Modified
- 2026-08-20T03:54:30.344401402Z
- Severity
-
- 9.3 (Critical) CVSS_V4 - 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 CVSS Calculator
- Summary
- ZEBRA: Consensus divergence via P2SH sigop undercount in pure-Rust disabled-opcode parser
- Details
-
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, p2shinputsigopcount used the pure-Rust script::Code::sigopcount path, whose tryfold parser stops at disabled opcodes such as OPCODESEPARATOR 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 MAXBLOCK_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.
- Database specific
{ "cna_assigner": "GitHub_M", "cwe_ids": [ "CWE-684" ], "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52735.json" }- References
-
- https://github.com/ZcashFoundation/zebra/releases/tag/v4.5.0
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52735.json
- https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-gf9r-m956-97qx
- https://nvd.nist.gov/vuln/detail/CVE-2026-52735
- https://github.com/ZcashFoundation/zebra/commit/1440b43ca7df59aca948090d45117557b217a6cd