CVE-2026-32134 NanoMQ: NULL Pointer Dereference Crash in tcptran_pipe_peer During Session Restore
Remote unauthenticated attackers can crash the NanoMQ MQTT broker via a null pointer dereference during session restoration under high-concurrency reconnect traffic.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-32134?
CVE-2026-32134 is a medium-severity vulnerability in nanomq NanoNNG, published on 19 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
NanoMQ MQTT Broker (NanoMQ) is an all-around Edge Messaging Platform. In versions 0.24.10 and below, when NanoMQ handles high-concurrency reconnect traffic using a reconnect-collision payload, the broker can crash due to a NULL pointer dereference during MQTT session resumption for clean_start=0 clients. The transport's p_peer callback (tcptran_pipe_peer()) iterates cpipe->subinfol while copying session metadata from the cached old pipe to the new reconnecting pipe, without checking whether the pointer is NULL. Under a reconnect race, cpipe->subinfol can be freed and set to NULL before session restore invokes this function, resulting in a remote unauthenticated Denial-of-Service (process crash) condition. This issue has been fixed in version 0.24.11.
Weakness: CWE-476
Which versions are affected by CVE-2026-32134?
How do I fix CVE-2026-32134?
No fix has been published for CVE-2026-32134 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-32134 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-32134 exists.
Sources
Also known as GHSA-q36f-83mh-pcv2.