# CVE-2021-20999: WEIDMUELLER: Accidentally open network port in u-controls and IoT-Gateways

> Attackers can access an internal network port on Weidmüller IoT gateways to manipulate devices or cause denial of service.

- **Severity:** Critical 9.4 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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:** 13 May 2021
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-3qph-f3mq-792v

## What is CVE-2021-20999?

CVE-2021-20999 is a critical vulnerability in Weidmüller IOT-GW30 (No. 2682620000), published on 13 May 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In Weidmüller u-controls and IoT-Gateways in versions up to 1.12.1 a network port intended only for device-internal usage is accidentally accessible via external network interfaces. By exploiting this vulnerability the device may be manipulated or the operation may be stopped.

Weakness: CWE-668 (Exposure of Resource to Wrong Sphere)

## Which versions are affected by CVE-2021-20999?

It affects 4 products.


Products: Weidmueller Iot-Gw30-4g-Eu Firmware, Weidmueller Iot-Gw30 Firmware, Weidmueller Uc20-Wl2000-Ac Firmware, Weidmueller Uc20-Wl2000-Iot Firmware.

## How do I fix CVE-2021-20999?

No fix has been published for CVE-2021-20999 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-20999 being exploited?

There is no known exploitation of CVE-2021-20999 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20999 and fix it if it is affected.

What it is: CVE-2021-20999 is a critical vulnerability in Weidmüller IOT-GW30 (No. 2682620000), published on 13 May 2021. 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-2021-20999 in the wild and no public exploit code.

Affected product: Weidmüller IOT-GW30 (No. 2682620000). 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-2021-20999/ (Markdown: https://insights.sbomify.com/CVE-2021-20999/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20999
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20999
- OSV: https://osv.dev/vulnerability/CVE-2021-20999

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-20999/
Summaries are generated and may contain mistakes; the official description above is the record.