CVE-2025-66023
January 01, 2026
NanoMQ MQTT Broker (NanoMQ) is an all-around Edge Messaging Platform. Versions prior to 0.24.5 have a Heap-Use-After-Free (UAF) vulnerability within the MQTT bridge client component (implemented via the underlying NanoNNG library). The vulnerability is triggered when NanoMQ acts as a bridge connecting to a remote MQTT broker. A malicious remote broker can trigger a crash (Denial of Service) or potential memory corruption by accepting the connection and immediately sending a malformed packet sequence. Version 0.34.5 contains a patch. The patch enforces stricter protocol adherence in the MQTT client SDK embedded in NanoMQ. Specifically, it ensures that CONNACK is always the first packet processed in the line. This prevents the state confusion that led to the Heap-Use-After-Free (UAF) when a malicious server sent a malformed packet sequence immediately after connection establishment. As a workaround, validate the remote broker before bridging.
Affected Packages
https://github.com/nanomq/NanoNNG.git (GITHUB):
Affected version(s) >=0.6.7 <0.24.5Fix Suggestion:
Update to version 0.24.5Related ResourcesĀ (3)
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Contact UsCVSS v4
Base Score:
6.9
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
PRESENT
Privileges Required
HIGH
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
HIGH
CVSS v3
Base Score:
5.8
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
HIGH
User Interaction
NONE
Scope
CHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
Use After Free
EPSS
Base Score:
0.05