CVE-2025-65953Network attack vector

Broker crash via premature retain-message cleanup

Published Nov 25, 2025 · Updated Nov 26, 2025

Use-after-free in NanoMQ before 0.22.5 allows remote attackers to crash the MQTT broker with malformed MQTT v5 retain traffic. NanoNNG's TCP transport in src/sp/transport/mqtt/broker_tcp.c prematurely cleans up message and pipe structures while processing the malformed properties. Reachability requires a client connection capable of sending the specific malformed retain-message sequence; exploitation interrupts service for all connected clients.

CVSS severity6.0
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Use-after-free in NanoMQ before 0.22.5 allows remote attackers to crash the MQTT broker with malformed MQTT v5 retain traffic. NanoNNG's TCP transport in src/sp/transport/mqtt/broker_tcp.c prematurely cleans up message and pipe structures while processing the malformed properties. Reachability requires a client connection capable of sending the specific malformed retain-message sequence; exploitation interrupts service for all connected clients.

The record

CVE
CVE-2025-65953
Published
Nov 25, 2025
Updated
Nov 26, 2025
Vendor
EMQ Technologies
Product
NanoMQ
Classifications
CWE-416, T1499.004
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Nov 25, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 26, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=< 0.22.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

EMQ Technologies · NanoMQversion=< 0.22.5

Published CVSS scores

6.0GitHub, Inc.CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1499.004Application or System Exploitation

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo