CVE-2023-29996Public exploitNetwork attack vector

Broker crash via zero-length topic cursor stall

Published May 4, 2023 · Updated Jan 29, 2025

NULL pointer dereference in NanoMQ 0.15.0-0 allows remote attackers to crash the MQTT broker with a crafted subscribe or unsubscribe packet. The subinfo_decode and unsubinfo_decode paths read a zero topic length but continue without advancing the payload cursor, leaving parsing stuck on the same field. Any unauthenticated client that can reach the MQTT listener can interrupt the broker; no data disclosure or modification is reported.

CVSS severity7.5
High
EPSS probability0.84%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in NanoMQ 0.15.0-0 allows remote attackers to crash the MQTT broker with a crafted subscribe or unsubscribe packet. The subinfo_decode and unsubinfo_decode paths read a zero topic length but continue without advancing the payload cursor, leaving parsing stuck on the same field. Any unauthenticated client that can reach the MQTT listener can interrupt the broker; no data disclosure or modification is reported.

The record

CVE
CVE-2023-29996
Published
May 4, 2023
Updated
Jan 29, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 4, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 29, 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

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-476NULL Pointer Dereference
T1499.004Application 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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