# CVE-2021-35394: Realtek Jungle SDK Remote Code Execution

> Remote unauthenticated attackers can execute arbitrary commands via the MP Daemon diagnostic tool in Realtek Jungle SDK.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 10 Dec 2021 (CISA KEV)
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 16 Aug 2021
- **Updated:** 21 Oct 2025
- **Also known as:** GHSA-9q9f-f28q-83xj

## What is CVE-2021-35394?

CVE-2021-35394 is a critical command injection vulnerability in n/a, published on 16 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Realtek Jungle SDK version v2.x up to v3.4.14B provides a diagnostic tool called 'MP Daemon' that is usually compiled as 'UDPServer' binary. The binary is affected by multiple memory corruption vulnerabilities and an arbitrary command injection vulnerability that can be exploited by remote unauthenticated attackers.

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

## Which versions are affected by CVE-2021-35394?

It affects 1 product.


Products: Realtek Rtl819x Jungle Software Development Kit.

## How do I fix CVE-2021-35394?

No fix has been published for CVE-2021-35394 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 24 Dec 2021.

## Is CVE-2021-35394 being exploited?

Yes. Attackers have exploited CVE-2021-35394 in the wild since at least 10 Dec 2021.

Public exploit code:

- RealTek AP Router SDK - Arbitrary Command Injection (nuclei)

## Other vulnerabilities in n/a

- [CVE-2021-35395](https://insights.sbomify.com/CVE-2021-35395/): Realtek AP-Router SDK Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2021-35393](https://insights.sbomify.com/CVE-2021-35393/): Memory corruption in n/a (critical 9.8)
- [CVE-2021-35392](https://insights.sbomify.com/CVE-2021-35392/): Memory corruption in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-35394 and fix it if it is affected.

What it is: CVE-2021-35394 is a critical command injection vulnerability in n/a, published on 16 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2021-35394 in the wild since at least 10 Dec 2021.

Affected product: n/a. 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-2021-35394/ (Markdown: https://insights.sbomify.com/CVE-2021-35394/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-35394
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-35394
- OSV: https://osv.dev/vulnerability/CVE-2021-35394

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-35394/
Summaries are generated and may contain mistakes; the official description above is the record.