{"cve":"CVE-2026-52739","nvd":{"published":"2026-08-18T20:17:18.127","modified":"2026-09-09T21:13:25.910","status":"Deferred","description":"ZEBRA is a Zcash node written entirely in Rust. Prior to 4.5.0, a malicious block producer can terminate zebrad by placing the same shielded transaction in a non-finalized parent block and its child. In zebra-state/src/service/non_finalized_state/chain.rs, Chain::push originally inserted the transaction hash into tx_loc_by_hash and asserted uniqueness before updating shielded data and running the duplicate Sprout, Sapling, or Orchard nullifier checks. The repeated transaction therefore reached the transactions must be unique within a single chain assertion before contextual validation could reject it cleanly. Zebra release builds use panic equals abort, so the reachable assertion terminates the entire process; exploitation requires either two consecutive attacker-mined blocks or an attacker-mined child immediately after an honest block includes the attacker's shielded transaction. This issue is fixed in version 4.5.0.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","score":5.9},"cwes":["CWE-248"],"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-hhm7-qrv5-h4r6"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:49:10.689564601+00:00"},"epss":{"cve":"CVE-2026-52739","score":0.00515,"percentile":0.43922,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-hhm7-qrv5-h4r6","url":"https://osv.dev/vulnerability/GHSA-hhm7-qrv5-h4r6","summary":"Zebra: Repeated Non-Finalized Shielded Transaction Aborts Zebra Before Duplicate-Nullifier Rejection","modified":"2026-07-02T20:11:29.946365Z","packages":[{"ecosystem":"crates.io","name":"zebra-state","purl":"pkg:cargo/zebra-state","ranges":["<7.0.0"],"fixed":["7.0.0"]},{"ecosystem":"crates.io","name":"zebrad","purl":"pkg:cargo/zebrad","ranges":["<4.5.0"],"fixed":["4.5.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}