# CVE-2017-5159: Misconfiguration in Phoenix Contact mGuard 8.4.0

> Updating Phoenix Contact mGuard devices resets the admin password to default, allowing unauthorized administrative access.

- **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:** 13 Feb 2017
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-xh78-5j99-gwm4

## What is CVE-2017-5159?

CVE-2017-5159 is a critical vulnerability in Phoenix Contact mGuard 8.4.0, published on 13 Feb 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered on Phoenix Contact mGuard devices that have been updated to Version 8.4.0. When updating an mGuard device to Version 8.4.0 via the update-upload facility, the update will succeed, but it will reset the password of the admin user to its default value.

Weakness: CWE-99 (Improper Control of Resource Identifiers)

## Which versions are affected by CVE-2017-5159?

It affects 1 product.


Products: Phoenixcontact Mguard Firmware.

## How do I fix CVE-2017-5159?

No fix has been published for CVE-2017-5159 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-5159 being exploited?

There is no known exploitation of CVE-2017-5159 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-5159 and fix it if it is affected.

What it is: CVE-2017-5159 is a critical vulnerability in Phoenix Contact mGuard 8.4.0, published on 13 Feb 2017. 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-2017-5159 in the wild and no public exploit code.

Affected product: Phoenix Contact mGuard 8.4.0. 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-2017-5159/ (Markdown: https://insights.sbomify.com/CVE-2017-5159/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-5159
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-5159
- OSV: https://osv.dev/vulnerability/CVE-2017-5159

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From sbomify Insights: https://insights.sbomify.com/CVE-2017-5159/
Summaries are generated and may contain mistakes; the official description above is the record.