# CVE-2020-10071: Insufficient publish message length validation in MQTT

> Insufficient length validation in Zephyr MQTT parsing allows buffer overflow, potentially enabling remote code execution.

- **Severity:** Critical 9.0 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/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:** 5 Jun 2020
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-x73g-qmcm-3qgq

## What is CVE-2020-10071?

CVE-2020-10071 is a critical memory corruption vulnerability in Zephyrproject Zephyr, published on 5 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The Zephyr MQTT parsing code performs insufficient checking of the length field on publish messages, allowing a buffer overflow and potentially remote code execution. NCC-ZEP-031 This issue affects: zephyrproject-rtos zephyr version 2.2.0 and later versions.

Weakness: CWE-129 (Improper Validation of Array Index), CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2020-10071?

It affects 1 product.


Products: Zephyrproject Zephyr.

## How do I fix CVE-2020-10071?

No fix has been published for CVE-2020-10071 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-10071 being exploited?

There is no known exploitation of CVE-2020-10071 in the wild and no public exploit code.

## Other vulnerabilities in Zephyrproject Zephyr

- [CVE-2026-5067](https://insights.sbomify.com/CVE-2026-5067/): Out-of-bounds read/write in HTTP WebSocket upgrade via non-null-terminated Sec-WebSocket-Key (critical 9.8)
- [CVE-2022-3806](https://insights.sbomify.com/CVE-2022-3806/): Bluetooth HCI Error Handling Double Free (critical 9.8)
- [CVE-2017-14199](https://insights.sbomify.com/CVE-2017-14199/): Memory corruption in getaddrinfo (critical 9.8)
- [CVE-2018-1000800](https://insights.sbomify.com/CVE-2018-1000800/): Null dereference in n/a (critical 9.8)
- [CVE-2021-3329](https://insights.sbomify.com/CVE-2021-3329/): DOS: Incorrect handling of the initial HCI ACL_MTU handshake packet leads to crash of bluetooth host layer (critical 9.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-10071 and fix it if it is affected.

What it is: CVE-2020-10071 is a critical memory corruption vulnerability in Zephyrproject Zephyr, published on 5 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-10071 in the wild and no public exploit code.

Affected product: Zephyrproject Zephyr. 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-2020-10071/ (Markdown: https://insights.sbomify.com/CVE-2020-10071/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-10071
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-10071
- OSV: https://osv.dev/vulnerability/CVE-2020-10071

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-10071/
Summaries are generated and may contain mistakes; the official description above is the record.