Vulnerability Description
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 Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Emqx | Nanomq | < 0.24.5 |
Related Weaknesses (CWE)
References
- https://github.com/nanomq/NanoNNG/pull/1365Issue TrackingPatch
- https://github.com/nanomq/nanomq/issues/2145Issue Tracking
- https://github.com/nanomq/nanomq/security/advisories/GHSA-24f7-q5hh-27hfVendor Advisory
FAQ
What is CVE-2025-66023?
CVE-2025-66023 is a vulnerability with a CVSS score of 4.9 (MEDIUM). 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 t...
How severe is CVE-2025-66023?
CVE-2025-66023 has been rated MEDIUM with a CVSS base score of 4.9/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2025-66023?
Check the references section above for vendor advisories and patch information. Affected products include: Emqx Nanomq.