CVE-2025-59946 NanoMQ has a Use After Free vulnerability via sub info list

High 7.5 Published 27 Dec 2025 Updated 29 Dec 2025

A race condition in NanoMQ's subscription info list can cause a heap use-after-free crash, leading to denial of service.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2025-59946?

CVE-2025-59946 is a high-severity use after free vulnerability in nanomq, published on 27 Dec 2025. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

NanoMQ MQTT Broker (NanoMQ) is an Edge Messaging Platform. Prior to version 0.24.2, there is a classical data racing issue about sub info list which could result in heap use after free crash. This issue has been patched in version 0.24.2.

Weakness: CWE-416

Which versions are affected by CVE-2025-59946?

It affects 1 product.

Products include Emqx Nanomq.

How do I fix CVE-2025-59946?

No fix has been published for CVE-2025-59946 yet. Limit exposure of the affected software until one is available.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2025-59946 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-59946 exists.

Sources

Also known as GHSA-xg37-23w7-72p5.