# CVE-2023-34488: Memory corruption in n/a

> A one-byte heap over-read in NanoMQ allows attackers to cause a denial of service via malformed MQTT messages.

- **Severity:** High 8.0 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 12 Jun 2023
- **Updated:** 29 Aug 2025
- **Also known as:** GHSA-fm3v-8h6r-vmxw

## What is CVE-2023-34488?

CVE-2023-34488 is a high-severity memory corruption vulnerability in n/a, published on 12 Jun 2023. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

NanoMQ 0.17.5 has a one-byte heap-based buffer over-read in the conn_handler function of mqtt_parser.c when it processes malformed messages.

Weakness: CWE-787 (Out-of-bounds Write), CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2023-34488?

It affects 1 product.


Products: Emqx Nanomq.

## How do I fix CVE-2023-34488?

No fix has been published for CVE-2023-34488 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-34488 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-34488 exists.

## Other vulnerabilities in n/a

- [CVE-2024-42655](https://insights.sbomify.com/CVE-2024-42655/): Missing authorization in n/a (high 8.8)
- [CVE-2025-59947](https://insights.sbomify.com/CVE-2025-59947/): NanoMQ has Buffer Overflow (high 8.5)
- [CVE-2026-32135](https://insights.sbomify.com/CVE-2026-32135/): NanoMQ has Heap Buffer Overflow in URI Parameter Parsing (high 7.7)
- [CVE-2026-36590](https://insights.sbomify.com/CVE-2026-36590/): Denial of service in n/a (high 7.5)
- [CVE-2026-21888](https://insights.sbomify.com/CVE-2026-21888/): MQTT v5 Variable Byte Integer parsing out-of-bounds: get_var_integer() (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-34488 and fix it if it is affected.

What it is: CVE-2023-34488 is a high-severity memory corruption vulnerability in n/a, published on 12 Jun 2023. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-34488 exists.

Affected product: n/a. 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-2023-34488/ (Markdown: https://insights.sbomify.com/CVE-2023-34488/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-34488
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-34488
- OSV: https://osv.dev/vulnerability/CVE-2023-34488

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-34488/
Summaries are generated and may contain mistakes; the official description above is the record.