CVE-2026-52739 ZEBRA: Repeated Non-Finalized Shielded Transaction Aborts Zebra Before Duplicate-Nullifier Rejection

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/nonfinalizedstate/chain.rs, Chain::push originally inserted the...

CVE-2026-52739

Affected: zebrad up to v4.4.1. Root cause: Chain::push in zebra-state/src/service/non_finalized_state/chain.rs:1608-1628 inserts the transaction hash into tx_loc_by_hash with an assert_eq! before running the duplicate shielded-nullifier guard, so a repeated shielded transaction in a child block t...

PT-2026-55396

Am I affected You are affected if: 1. You run zebrad up to and including v4.4.1. 2. Your node processes blocks past the checkpoint height non-finalized state is active. 3. The network has NU5 or later activated. All default configurations are affected. Summary Chain::push in the non-finalized sta...

PT-2026-55475

Name of the Vulnerable Software and Affected Versions ZEBRA versions prior to 4.5.0 Description A malicious block producer can cause the zebrad process to terminate by placing the same shielded transaction in a non-finalized parent block and its child. In the Chain::push function within...