# CVE-2021-47816: Thecus N4800Eco Nas Server Control Panel - Command Injection

> Authenticated attackers can execute arbitrary system commands with administrative privileges via user management endpoints in Thecus NAS servers.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 16 Jan 2026
- **Updated:** 28 Jul 2026
- **Also known as:** GHSA-6qxr-24qm-qr24

## What is CVE-2021-47816?

CVE-2021-47816 is a medium-severity command injection vulnerability in Thecus N4800Eco Nas Server Control Panel, published on 16 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Thecus N4800Eco NAS Server Control Panel contains a command injection vulnerability that allows authenticated attackers to execute arbitrary system commands through user management endpoints. Attackers can inject commands via username and batch user creation parameters to execute shell commands with administrative privileges.

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

## Which versions are affected by CVE-2021-47816?


## How do I fix CVE-2021-47816?

No fix has been published for CVE-2021-47816 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-47816 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-47816 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-47816 and fix it if it is affected.

What it is: CVE-2021-47816 is a medium-severity command injection vulnerability in Thecus N4800Eco Nas Server Control Panel, published on 16 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-47816 exists.

Affected product: Thecus N4800Eco Nas Server Control Panel. 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-2021-47816/ (Markdown: https://insights.sbomify.com/CVE-2021-47816/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47816
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47816
- OSV: https://osv.dev/vulnerability/CVE-2021-47816

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47816/
Summaries are generated and may contain mistakes; the official description above is the record.