CVE-2026-22040 NanoMQ 0.24.6 Use-After-Free Leading to Heap Corruption and Broker Crash

Medium 5.3 Published 4 Mar 2026 Updated 5 Mar 2026

Attackers can crash the NanoMQ MQTT broker by triggering heap corruption via specific traffic patterns, causing a denial of service.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2026-22040?

CVE-2026-22040 is a medium-severity use after free vulnerability in nanomq, published on 4 Mar 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

NanoMQ MQTT Broker (NanoMQ) is an all-around Edge Messaging Platform. In version 0.24.6, by generating a combined traffic pattern of high-frequency publishes and rapid reconnect/kick-out using the same ClientID and massive subscribe/unsubscribe jitter, it is possible to reliably trigger heap memory corruption in the Broker process, causing it to exit immediately with SIGABRT due to free(): invalid pointer. As of time of publication, no known patched versions are available.

Weakness: CWE-416

Which versions are affected by CVE-2026-22040?

It affects 1 product.

Products include Emqx Nanomq.

How do I fix CVE-2026-22040?

No fix has been published for CVE-2026-22040 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-2026-22040 being exploited?

There is no known exploitation of CVE-2026-22040 in the wild and no public exploit code.

Sources

Also known as GHSA-v57q-w88m-424r.