CVE-2026-52739
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
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.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| ZcashFoundation | zebra | < 4.5.0 | affected |
| ZcashFoundation | zebra-state | < 7.0.0 | affected |
Weaknesses
- CWE-248: CWE-248: Uncaught Exception
References
- https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-hhm7-qrv5-h4r6
- https://github.com/ZcashFoundation/zebra/commit/1440b43ca7df59aca948090d45117557b217a6cd
- https://github.com/ZcashFoundation/zebra/releases/tag/v4.5.0
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