ZEBRA is a Zcash node written entirely in Rust. Prior to 4.5.0, a remote unauthenticated P2P peer can stall a Zebra node by racing an invalid block body against the valid canonical body for the same block header hash. ZIP-244 permits the attacker to mutate coinbase scriptSig authentication data while retaining the transaction identifiers, merkle root, and block header hash, so the poisoned body fails later commitment validation but shares the canonical hash. In zebra-state/src/service.rs, queue_and_commit_to_non_finalized_state recorded the hash in non_finalized_block_write_sent_hashes before contextual validation completed and did not remove it when the write task rejected the body. When the honest body later arrived, the cached hash caused KnownBlock::WriteChannel duplicate handling to suppress it, leaving the node stuck one height behind until restart or reorganization. This issue is fixed in version 4.5.0.
Metrics
Affected Vendors & Products
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Advisories
| Source | ID | Title |
|---|---|---|
 Github GHSA |
GHSA-4m69-67m6-prqp | Zebra has block suppression via NU5 same-header body poisoning of sent-hash cache |
Fixes
Solution
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Workaround
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References
History
Tue, 18 Aug 2026 19:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | ZEBRA is a Zcash node written entirely in Rust. Prior to 4.5.0, a remote unauthenticated P2P peer can stall a Zebra node by racing an invalid block body against the valid canonical body for the same block header hash. ZIP-244 permits the attacker to mutate coinbase scriptSig authentication data while retaining the transaction identifiers, merkle root, and block header hash, so the poisoned body fails later commitment validation but shares the canonical hash. In zebra-state/src/service.rs, queue_and_commit_to_non_finalized_state recorded the hash in non_finalized_block_write_sent_hashes before contextual validation completed and did not remove it when the write task rejected the body. When the honest body later arrived, the cached hash caused KnownBlock::WriteChannel duplicate handling to suppress it, leaving the node stuck one height behind until restart or reorganization. This issue is fixed in version 4.5.0. | |
| Title | ZEBRA: Block suppression via NU5 same-header body poisoning of sent-hash cache | |
| Weaknesses | CWE-459 | |
| References |
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| Metrics |
cvssV4_0
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Projects
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MITRE
Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-08-18T19:38:44.395Z
Reserved: 2026-06-08T14:00:43.572Z
Link: CVE-2026-52736
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
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Weaknesses