# CVE-2021-20708: Command injection in NEC Aterm devices

> Authenticated attackers can execute arbitrary OS commands on NEC Aterm routers via crafted requests, requiring firmware updates to mitigate.

- **Severity:** High 7.2 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 Apr 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-w32w-5vr5-g3ph

## What is CVE-2021-20708?

CVE-2021-20708 is a high-severity command injection vulnerability in NEC Aterm devices, published on 26 Apr 2021. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

NEC Aterm devices (Aterm WF1200CR firmware Ver1.3.2 and earlier, Aterm WG1200CR firmware Ver1.3.3 and earlier, and Aterm WG2600HS firmware Ver1.5.1 and earlier) allow authenticated attackers to execute arbitrary OS commands by sending a specially crafted request to a specific URL.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2021-20708?

It affects 3 products.


Products: Nec Aterm Wf1200cr Firmware, Nec Aterm Wg1200cr Firmware, Nec Aterm Wg2600hs Firmware.

## How do I fix CVE-2021-20708?

No fix has been published for CVE-2021-20708 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-20708 being exploited?

There is no known exploitation of CVE-2021-20708 in the wild and no public exploit code.

## Other vulnerabilities in NEC Aterm devices

- [CVE-2018-16195](https://insights.sbomify.com/CVE-2018-16195/): Command injection in Aterm WF1200CR and Aterm WG1200CR (high 8.8)
- [CVE-2021-20709](https://insights.sbomify.com/CVE-2021-20709/): Command injection in NEC Aterm devices (high 7.2)
- [CVE-2018-16194](https://insights.sbomify.com/CVE-2018-16194/): Command injection in Aterm WF1200CR and Aterm WG1200CR (high 7.2)
- [CVE-2018-16192](https://insights.sbomify.com/CVE-2018-16192/): Information disclosure in Aterm WF1200CR and Aterm WG1200CR (medium 6.5)
- [CVE-2018-16193](https://insights.sbomify.com/CVE-2018-16193/): Cross-site scripting in Aterm WF1200CR and Aterm WG1200CR (medium 5.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20708 and fix it if it is affected.

What it is: CVE-2021-20708 is a high-severity command injection vulnerability in NEC Aterm devices, published on 26 Apr 2021. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-20708 in the wild and no public exploit code.

Affected product: NEC Aterm devices. 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-2021-20708/ (Markdown: https://insights.sbomify.com/CVE-2021-20708/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20708
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20708
- OSV: https://osv.dev/vulnerability/CVE-2021-20708

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-20708/
Summaries are generated and may contain mistakes; the official description above is the record.