# CVE-2020-10062: Packet length decoding error in MQTT

> An off-by-one error in the Zephyr RTOS MQTT packet length decoder allows remote attackers to cause memory corruption and potentially execute arbitrary code.

- **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-5rf5-gcg9-hrpr

## What is CVE-2020-10062?

CVE-2020-10062 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

An off-by-one error in the Zephyr project MQTT packet length decoder can result in memory corruption and possible remote code execution. NCC-ZEP-031 This issue affects: zephyrproject-rtos zephyr version 2.2.0 and later versions.

Weakness: CWE-193 (Off-by-one Error)

## Which versions are affected by CVE-2020-10062?

It affects 1 product.


Products: Zephyrproject Zephyr.

## How do I fix CVE-2020-10062?

No fix has been published for CVE-2020-10062 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-10062 being exploited?

There is no known exploitation of CVE-2020-10062 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-2020-10062 and fix it if it is affected.

What it is: CVE-2020-10062 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-2020-10062 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-2020-10062/ (Markdown: https://insights.sbomify.com/CVE-2020-10062/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-10062
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-10062
- OSV: https://osv.dev/vulnerability/CVE-2020-10062

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-10062/
Summaries are generated and may contain mistakes; the official description above is the record.