CVE-2025-66023
4.9 · MEDIUMOverview
CVE-2025-66023 is a medium-severity vulnerability affecting emqx nanomq. It was published on January 1, 2026 and has a CVSS 3.1 base score of 4.9 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 4.9, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
Technical 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.
Remediation
Check the references section for vendor advisories and patches from emqx. Update nanomq to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| emqx | nanomq | >= 0, < 0.24.5 | Affected |
Frequently Asked Questions
What is CVE-2025-66023?
CVE-2025-66023 is a medium-severity vulnerability affecting emqx nanomq. It was published on January 1, 2026 and has a CVSS 3.1 base score of 4.9 (MEDIUM).
How severe is CVE-2025-66023?
This vulnerability has a CVSS 3.1 base score of 4.9, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2025-66023?
Check the references section for vendor advisories and patches from emqx. Update nanomq to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2025-66023?
CyberStrike's AI-powered security agents can automatically detect CVE-2025-66023 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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