# CVE-2025-66620: Columbia Weather Systems MicroServer Command Shell in Externally Accessible Directory

> An attacker with admin access can exploit an unused webshell to gain shell access, modify data, and establish persistence on the MicroServer.

- **Severity:** High 8.6 (`CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 7 Jan 2026
- **Updated:** 7 Jan 2026
- **Also known as:** GHSA-mh3m-m8m5-x43f

## What is CVE-2025-66620?

CVE-2025-66620 is a high-severity command injection vulnerability in Columbia Weather Systems MicroServer, published on 7 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An unused webshell in MicroServer allows unlimited login attempts, with sudo rights on certain files and directories. An attacker with admin access to MicroServer can gain limited shell access, enabling persistence through reverse shells, and the ability to modify or remove data stored in the file system.

Weakness: CWE-553 (Command Shell in Externally Accessible Directory)

## Which versions are affected by CVE-2025-66620?

It affects 1 product.


Products: Columbiaweather Weather Microserver Firmware.

## How do I fix CVE-2025-66620?

No fix has been published for CVE-2025-66620 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-66620 being exploited?

There is no known exploitation of CVE-2025-66620 in the wild and no public exploit code.

## Other vulnerabilities in Columbia Weather Systems MicroServer

- [CVE-2018-18877](https://insights.sbomify.com/CVE-2018-18877/): Missing authorization in n/a (high 8.8)
- [CVE-2018-18879](https://insights.sbomify.com/CVE-2018-18879/): Command injection in n/a (high 8.8)
- [CVE-2025-61939](https://insights.sbomify.com/CVE-2025-61939/): Columbia Weather Systems MicroServer Improper Restriction of Communication Channel to Intended Endpoints (high 8.7)
- [CVE-2018-18878](https://insights.sbomify.com/CVE-2018-18878/): Denial of service in n/a (high 7.5)
- [CVE-2018-18875](https://insights.sbomify.com/CVE-2018-18875/): Cross-site scripting in n/a (medium 5.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-66620 and fix it if it is affected.

What it is: CVE-2025-66620 is a high-severity command injection vulnerability in Columbia Weather Systems MicroServer, published on 7 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-66620 in the wild and no public exploit code.

Affected product: Columbia Weather Systems MicroServer. 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-2025-66620/ (Markdown: https://insights.sbomify.com/CVE-2025-66620/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-66620
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-66620
- OSV: https://osv.dev/vulnerability/CVE-2025-66620

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-66620/
Summaries are generated and may contain mistakes; the official description above is the record.