CVE-2026-52736Network attack vector

Node stall via stale sent-hash cache

Published Aug 18, 2026 · Updated Aug 18, 2026

Denial of service in Zcash Foundation Zebra before 4.5.0 allows remote attackers to stall node synchronization via crafted P2P block bodies. In queue_and_commit_to_non_finalized_state in zebra-state/src/service.rs, Zebra adds a block hash to non_finalized_block_write_sent_hashes before contextual validation completes and does not remove it when the write task rejects a poisoned body that shares the canonical header hash. Exploitation requires winning the race to supply the malformed body before honest peers deliver the valid block, after which the node remains one height behind until restart or chain reorganization.

CVSS severity8.7
High
EPSS probability0.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Zcash Foundation Zebra before 4.5.0 allows remote attackers to stall node synchronization via crafted P2P block bodies. In queue_and_commit_to_non_finalized_state in zebra-state/src/service.rs, Zebra adds a block hash to non_finalized_block_write_sent_hashes before contextual validation completes and does not remove it when the write task rejects a poisoned body that shares the canonical header hash. Exploitation requires winning the race to supply the malformed body before honest peers deliver the valid block, after which the node remains one height behind until restart or chain reorganization.

The record

CVE
CVE-2026-52736
Published
Aug 18, 2026
Updated
Aug 18, 2026
Vendor
Zcash Foundation
Product
Zebra
Classifications
CWE-459, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 4.5.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zcash Foundation · Zebraversion=< 4.5.0

Published CVSS scores

8.7GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-459Incomplete Cleanup
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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