CVE-2025-59947Network attack vector

Heap overwrite via undersized delivery vector

Published Dec 15, 2025 · Updated Dec 15, 2025

Heap buffer overflow in NanoMQ before 0.24.4 allows remote authenticated users to corrupt broker memory via crafted PUBLISH traffic. The foreach_client function grows the existing msg_infos vector to only the new context count, then appends entries beyond that allocation. An authenticated MQTT client must reach a routing state where shared and ordinary subscriptions both match; the overwrite corrupts broker memory and terminates instrumented builds.

CVSS severity8.5
High
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in NanoMQ before 0.24.4 allows remote authenticated users to corrupt broker memory via crafted PUBLISH traffic. The foreach_client function grows the existing msg_infos vector to only the new context count, then appends entries beyond that allocation. An authenticated MQTT client must reach a routing state where shared and ordinary subscriptions both match; the overwrite corrupts broker memory and terminates instrumented builds.

The record

CVE
CVE-2025-59947
Published
Dec 15, 2025
Updated
Dec 15, 2025
Vendor
EMQ Technologies
Product
NanoMQ
Classifications
CWE-120, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 15, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 15, 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?

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

  1. Affected versionversion=< 0.24.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

EMQ Technologies · NanoMQversion=< 0.24.4

Published CVSS scores

9.0NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
8.5GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:H/VA:H/SC:L/SI:H/SA: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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499.004Application or System Exploitation

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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