CVE-2025-66023NanoMQ MQTT Broker (NanoMQ) is an all-around Edge Messaging Platform.

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.

CVSS

4.9 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

Weakness (CWE)

CWE-416

Known exploited

Not in CISA's KEV catalog

EPSS (exploitation in the next 30 days)

Not loaded for this CVE

Assigned by

Not given

NVD analysis

Analyzed

Record last updated

Jun 17, 2026

First seen by InfoSec Signals

Oct 9, 2026

The CVE record on cve.org · NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.