{"apiVersion":"1.0","identifier":"CVE-2026-52739","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.","publishedAt":"2026-08-18T20:17:18","lastModifiedAt":"2026-08-19T19:17:18","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-52739","cvssScore":5.9,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","epssProbability":0.00394,"riskScore":0.61,"affectedProduct":"Zebra","affectedVersions":"<4.5.0","vulnerabilityType":"Other","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-52739","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-52739","en":"https://www.redsauce.net/en/cves/CVE-2026-52739","fr":"https://www.redsauce.net/fr/cves/CVE-2026-52739","pt":"https://www.redsauce.net/pt/cves/CVE-2026-52739","de":"https://www.redsauce.net/de/cves/CVE-2026-52739","sk":"https://www.redsauce.net/sk/cves/CVE-2026-52739","el":"https://www.redsauce.net/el/cves/CVE-2026-52739"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-52739"}}