{"id":"CVE-2026-52739","summary":"ZEBRA: Repeated Non-Finalized Shielded Transaction Aborts Zebra Before Duplicate-Nullifier Rejection","details":"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.","aliases":["GHSA-hhm7-qrv5-h4r6"],"modified":"2026-08-21T03:30:24.989909154Z","published":"2026-08-18T19:22:19.865Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-248"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52739.json","unresolved_ranges":[{"extracted_events":[{"fixed":"7.0.0"}],"source":"AFFECTED_FIELD"}]},"references":[{"type":"WEB","url":"https://github.com/ZcashFoundation/zebra/releases/tag/v4.5.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52739.json"},{"type":"ADVISORY","url":"https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-hhm7-qrv5-h4r6"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-52739"},{"type":"FIX","url":"https://github.com/ZcashFoundation/zebra/commit/1440b43ca7df59aca948090d45117557b217a6cd"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/zcashfoundation/zebra","events":[{"introduced":"0"},{"fixed":"1440b43ca7df59aca948090d45117557b217a6cd"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"4.5.0"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["v4.4.0","v4.4.1","v4.3.1","4.3.1","v4.3.0","v4.2.0","v4.1.0","v4.0.0","v3.1.0","v3.0.0","v3.0.0-rc.0","v2.5.0","v2.0.1","v2.4.2","v2.3.0","v2.4.0","v2.0.0","v2.2.0","v2.1.0","v2.0.0-rc.0","v1.9.0","v1.8.0","v1.7.0","v1.6.1","v1.6.0","v1.5.2","v1.5.1","v1.5.0","v1.4.0","v1.3.0","v1.2.0","v1.1.0","v1.0.1","v1.0.0","v1.0.0-rc.9","v1.0.0-rc.8","v1.0.0-rc.7","v1.0.0-rc.6","v1.0.0-rc.5","v1.0.0-rc.0","v1.0.0-rc.4","v1.0.0-rc.3","v1.0.0-rc.2","v1.0.0-rc.1","v1.0.0-beta.15","v1.0.0-beta.14","v1.0.0-beta.13","v1.0.0-beta.12","v1.0.0-beta.11","v1.0.0-beta.10","v1.0.0-beta.9","v1.0.0-beta.8","v1.0.0-beta.7","v1.0.0-beta.6","v1.0.0-beta.5","v1.0.0-beta.4","v1.0.0-beta.3","v1.0.0-beta.2","v1.0.0-beta.1","v1.0.0-beta.0","v1.0.0-alpha.19","v1.0.0-alpha.18","v1.0.0-alpha.17","v1.0.0-alpha.16","v1.0.0-alpha.15","v1.0.0-alpha.14","v1.0.0-alpha.13","v1.0.0-alpha.12","v1.0.0-alpha.11","v1.0.0-alpha.10","v1.0.0-alpha.9","v1.0.0-alpha.8","v1.0.0-alpha.7","v1.0.0-alpha.6","v1.0.0-alpha.5","v1.0.0-alpha.4","v1.0.0-alpha.3","v1.0.0-alpha.2","v1.0.0-alpha.1","v1.0.0-alpha.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-52739.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}