# CVE-2021-26621: Netis Korea MEX01 Buffer overflow vulnerability

> Remote attackers can execute arbitrary code on Netis MEX01 devices via a buffer overflow in the strcpy function.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/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:** 25 Mar 2022
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-8gwh-x546-9265

## What is CVE-2021-26621?

CVE-2021-26621 is a high-severity memory corruption vulnerability in NetU Corp. MEX01, published on 25 Mar 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An Buffer Overflow vulnerability leading to remote code execution was discovered in MEX01. Remote attackers can use this vulnerability by using the property that the target program copies parameter values to memory through the strcpy() function.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2021-26621?

It affects 1 product.


Products: Netu Mex01 Firmware.

## How do I fix CVE-2021-26621?

No fix has been published for CVE-2021-26621 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-26621 being exploited?

There is no known exploitation of CVE-2021-26621 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-26621 and fix it if it is affected.

What it is: CVE-2021-26621 is a high-severity memory corruption vulnerability in NetU Corp. MEX01, published on 25 Mar 2022. 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-2021-26621 in the wild and no public exploit code.

Affected product: NetU Corp. MEX01. 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-2021-26621/ (Markdown: https://insights.sbomify.com/CVE-2021-26621/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-26621
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-26621
- OSV: https://osv.dev/vulnerability/CVE-2021-26621

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-26621/
Summaries are generated and may contain mistakes; the official description above is the record.