CVE-2026-52739

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 v3 5.9 MEDIUM

5.9^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.2 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
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

Configurations

No configuration.

History

No history.

Information

Published : 2026-08-18 20:17

Updated : 2026-09-09 21:13

NVD link : CVE-2026-52739

Mitre link : CVE-2026-52739

CVE.ORG link : CVE-2026-52739

JSON object : View

Products Affected

No product.

CWE

CWE-248

Uncaught Exception

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