# 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.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 May 2026
- **Updated:** 19 May 2026
- **Also known as:** GHSA-q36f-83mh-pcv2

## 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 (NULL Pointer Dereference)

## 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.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-32134 and fix it if it is affected.

What it is: 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-32134 exists.

Affected product: nanomq NanoNNG. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-32134/ (Markdown: https://insights.sbomify.com/CVE-2026-32134/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-32134
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-32134
- OSV: https://osv.dev/vulnerability/CVE-2026-32134

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-32134/
Summaries are generated and may contain mistakes; the official description above is the record.