CVE-2026-52732Network attack vector

Mempool admission denial via peer queue saturation

Published Aug 18, 2026 · Updated Aug 18, 2026

Denial of service in Zebra before 4.5.0 allows remote attackers to block mempool transaction admission via crafted P2P inv messages. In zebrad/src/components/mempool/downloads.rs, a single global 25-slot download and verification queue lacks per-peer accounting, and zebrad/src/components/inbound.rs converts FullQueue into Response::Nil so overload never reaches peer disconnection handling. Any unauthenticated peer that advertises fake transaction IDs and then withholds the transactions can keep refilling expired slots, denying honest peer traffic and local sendrawtransaction requests while block validation and synchronization continue.

CVSS severity5.3
Medium
EPSS probability0.37%
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 Zebra before 4.5.0 allows remote attackers to block mempool transaction admission via crafted P2P inv messages. In zebrad/src/components/mempool/downloads.rs, a single global 25-slot download and verification queue lacks per-peer accounting, and zebrad/src/components/inbound.rs converts FullQueue into Response::Nil so overload never reaches peer disconnection handling. Any unauthenticated peer that advertises fake transaction IDs and then withholds the transactions can keep refilling expired slots, denying honest peer traffic and local sendrawtransaction requests while block validation and synchronization continue.

The record

CVE
CVE-2026-52732
Published
Aug 18, 2026
Updated
Aug 18, 2026
Vendor
Zcash Foundation
Product
Zebra
Classifications
CWE-770, 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

5.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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-770Allocation of Resources Without Limits or Throttling
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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