# CVE-2020-6985: Hardcoded credentials in Moxa PT-7528 series firmware, Version 4.0 or lower, PT-7828 series firmware, Version 3.9 or lower

> Hard-coded service code allows unauthorized console access on Moxa PT-7528 and PT-7828 series devices.

- **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:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Mar 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-gp77-fg8q-p93m

## What is CVE-2020-6985?

CVE-2020-6985 is a critical vulnerability in Moxa PT-7528 series firmware, Version 4.0 or lower, PT-7828 series firmware, Version 3.9 or lower, published on 24 Mar 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In Moxa PT-7528 series firmware, Version 4.0 or lower, and PT-7828 series firmware, Version 3.9 or lower, these devices use a hard-coded service code for access to the console.

Weakness: CWE-798 (Use of Hard-coded Credentials)

## Which versions are affected by CVE-2020-6985?

It affects 55 products.


Products: Moxa Pt-7528-12msc-12tx-4gsfp-Hv-Hv Firmware, Moxa Pt-7528-12msc-12tx-4gsfp-Hv Firmware, Moxa Pt-7528-12msc-12tx-4gsfp-Wv-Wv Firmware, Moxa Pt-7528-12msc-12tx-4gsfp-Wv Firmware, Moxa Pt-7528-12mst-12tx-4gsfp-Hv-Hv Firmware, Moxa Pt-7528-12mst-12tx-4gsfp-Hv Firmware, Moxa Pt-7528-12mst-12tx-4gsfp-Wv-Wv Firmware, Moxa Pt-7528-12mst-12tx-4gsfp-Wv Firmware, Moxa Pt-7528-16msc-8tx-4gsfp-Hv-Hv Firmware, Moxa Pt-7528-16msc-8tx-4gsfp-Hv Firmware, Moxa Pt-7528-16msc-8tx-4gsfp-Wv-Wv Firmware, Moxa Pt-7528-16msc-8tx-4gsfp-Wv Firmware, Moxa Pt-7528-16mst-8tx-4gsfp-Hv-Hv Firmware, Moxa Pt-7528-16mst-8tx-4gsfp-Hv Firmware, Moxa Pt-7528-16mst-8tx-4gsfp-Wv-Wv Firmware, Moxa Pt-7528-16mst-8tx-4gsfp-Wv Firmware, Moxa Pt-7528-20msc-4tx-4gsfp-Hv-Hv Firmware, Moxa Pt-7528-20msc-4tx-4gsfp-Hv Firmware, Moxa Pt-7528-20msc-4tx-4gsfp-Wv-Wv Firmware, Moxa Pt-7528-20msc-4tx-4gsfp-Wv Firmware and 35 more.

## How do I fix CVE-2020-6985?

No fix has been published for CVE-2020-6985 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-6985 being exploited?

There is no known exploitation of CVE-2020-6985 in the wild and no public exploit code.

## Other vulnerabilities in Moxa PT-7528 series firmware, Version 4.0 or lower, PT-7828 series firmware, Version 3.9 or lower

- [CVE-2020-6989](https://insights.sbomify.com/CVE-2020-6989/): Memory corruption in Moxa PT-7528 series firmware, Version 4.0 or lower, PT-7828 series firmware, Version 3.9 or lower (critical 9.8)
- [CVE-2020-6995](https://insights.sbomify.com/CVE-2020-6995/): Weak cryptography in Moxa PT-7528 series firmware, Version 4.0 or lower, PT-7828 series firmware, Version 3.9 or lower (critical 9.8)
- [CVE-2020-6983](https://insights.sbomify.com/CVE-2020-6983/): Hardcoded credentials in Moxa PT-7528 series firmware, Version 4.0 or lower, PT-7828 series firmware, Version 3.9 or lower (high 7.5)
- [CVE-2020-6987](https://insights.sbomify.com/CVE-2020-6987/): Weak cryptography in Moxa PT-7528 series firmware, Version 4.0 or lower, PT-7828 series firmware, Version 3.9 or lower (high 7.5)
- [CVE-2020-6993](https://insights.sbomify.com/CVE-2020-6993/): Information disclosure in Moxa PT-7528 series firmware, Version 4.0 or lower, PT-7828 series firmware, Version 3.9 or lower (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-6985 and fix it if it is affected.

What it is: CVE-2020-6985 is a critical vulnerability in Moxa PT-7528 series firmware, Version 4.0 or lower, PT-7828 series firmware, Version 3.9 or lower, published on 24 Mar 2020. 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-2020-6985 in the wild and no public exploit code.

Affected product: Moxa PT-7528 series firmware, Version 4.0 or lower, PT-7828 series firmware, Version 3.9 or lower. 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-2020-6985/ (Markdown: https://insights.sbomify.com/CVE-2020-6985/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-6985
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-6985
- OSV: https://osv.dev/vulnerability/CVE-2020-6985

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-6985/
Summaries are generated and may contain mistakes; the official description above is the record.