CVE-2023-28366Network attack vector

Service interruption via unbounded QoS 2 queues

Published Sep 1, 2023 · Updated Jun 26, 2025

Memory exhaustion in Eclipse Mosquitto 1.3.2 through 2.0.15 allows remote attackers to interrupt the broker via crafted QoS 2 traffic. The broker keeps a PUBREC packet queued after send returns EAGAIN and adds another for each duplicate message identifier without enforcing the outgoing-message limit. A remote MQTT client needs only to sustain this exchange; growing broker memory can interrupt service without exposing or modifying data.

CVSS severity7.5
High
EPSS probability1.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory exhaustion in Eclipse Mosquitto 1.3.2 through 2.0.15 allows remote attackers to interrupt the broker via crafted QoS 2 traffic. The broker keeps a PUBREC packet queued after send returns EAGAIN and adds another for each duplicate message identifier without enforcing the outgoing-message limit. A remote MQTT client needs only to sustain this exchange; growing broker memory can interrupt service without exposing or modifying data.

The record

CVE
CVE-2023-28366
Published
Sep 1, 2023
Updated
Jun 26, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-401, T1499.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 1, 2023CVE publishedPublication date reported by the CVE source.
  2. Jun 26, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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-401Missing Release of Memory after Effective Lifetime
T1499.002Service Exhaustion

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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