CVE-2023-34494Public exploitNetwork attack vector

Broker crash via pipe-reaper use-after-free race

Published Jun 12, 2023 · Updated Jan 3, 2025

Heap use-after-free in NanoMQ 0.16.5 allows remote attackers to crash its MQTT broker by sending malformed messages. The nano_ctx_send function in nmq_mqtt.c reads a pipe object while reap_worker can free that object through pipe_destroy, causing the sending thread to dereference freed heap memory. No authentication is required to submit the malformed network traffic, and successful triggering aborts the broker process and interrupts service for connected clients.

CVSS severity7.5
High
EPSS probability0.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap use-after-free in NanoMQ 0.16.5 allows remote attackers to crash its MQTT broker by sending malformed messages. The nano_ctx_send function in nmq_mqtt.c reads a pipe object while reap_worker can free that object through pipe_destroy, causing the sending thread to dereference freed heap memory. No authentication is required to submit the malformed network traffic, and successful triggering aborts the broker process and interrupts service for connected clients.

The record

CVE
CVE-2023-34494
Published
Jun 12, 2023
Updated
Jan 3, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-416, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 12, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 3, 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 exploitPublished

Weakness, pattern, technique

CWE-416Use After Free
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

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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