# CVE-2021-20989: Fibaro Home Center Insufficient remote access server authorization

> Attackers can bypass remote access security via DNS spoofing to intercept SSH connections and access the web management interface, requiring valid credentials for further actions.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 Apr 2021
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-j6x8-v233-x3mm

## What is CVE-2021-20989?

CVE-2021-20989 is a medium-severity vulnerability in Fibaro Home Center, published on 19 Apr 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Fibaro Home Center 2 and Lite devices with firmware version 4.600 and older initiate SSH connections to the Fibaro cloud to provide remote access and remote support capabilities. This connection can be intercepted using DNS spoofing attack and a device initiated remote port-forward channel can be used to connect to the web management interface. Knowledge of authorization credentials to the management interface is required to perform any further actions.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2021-20989?

It affects 2 products.


Products: Fibaro Home Center 2 Firmware, Fibaro Home Center Lite Firmware.

## How do I fix CVE-2021-20989?

No fix has been published for CVE-2021-20989 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-20989 being exploited?

There is no known exploitation of CVE-2021-20989 in the wild and no public exploit code.

## Other vulnerabilities in Fibaro Home Center

- [CVE-2021-20991](https://insights.sbomify.com/CVE-2021-20991/): Fibaro Home Center Authenticated remote command execution (critical 9.8)
- [CVE-2021-20992](https://insights.sbomify.com/CVE-2021-20992/): Fibaro Home Center Unencrypted management interface (high 8.1)
- [CVE-2021-20990](https://insights.sbomify.com/CVE-2021-20990/): Fibaro Home Center Unauthenticated access to shutdown, reboot and reboot to recovery mode (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20989 and fix it if it is affected.

What it is: CVE-2021-20989 is a medium-severity vulnerability in Fibaro Home Center, published on 19 Apr 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-2021-20989 in the wild and no public exploit code.

Affected product: Fibaro Home Center. 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-2021-20989/ (Markdown: https://insights.sbomify.com/CVE-2021-20989/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20989
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20989
- OSV: https://osv.dev/vulnerability/CVE-2021-20989

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-20989/
Summaries are generated and may contain mistakes; the official description above is the record.