# CVE-2018-20156: Code injection in n/a

> Authenticated site administrators can execute arbitrary PHP code across a multisite network via the WP Maintenance Mode plugin.

- **Severity:** High 7.2 (`CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Dec 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-fpm4-976c-9f33

## What is CVE-2018-20156?

CVE-2018-20156 is a high-severity code injection vulnerability in n/a, published on 14 Dec 2018. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

The WP Maintenance Mode plugin before 2.0.7 for WordPress allows remote authenticated "site administrator" users to execute arbitrary PHP code throughout a multisite network.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2018-20156?

It affects 1 product.


Products: Designmodo Wp Maintenance Mode.

## How do I fix CVE-2018-20156?

No fix has been published for CVE-2018-20156 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-20156 being exploited?

There is no known exploitation of CVE-2018-20156 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2018-20154](https://insights.sbomify.com/CVE-2018-20154/): Information disclosure in n/a (medium 4.3)
- [CVE-2018-20155](https://insights.sbomify.com/CVE-2018-20155/): The WP Maintenance Mode plugin before 2.0.7 for WordPress allows remote authenticated subscriber users to bypass intended access restriction (medium 4.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-20156 and fix it if it is affected.

What it is: CVE-2018-20156 is a high-severity code injection vulnerability in n/a, published on 14 Dec 2018. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-20156 in the wild and no public exploit code.

Affected product: n/a. 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-2018-20156/ (Markdown: https://insights.sbomify.com/CVE-2018-20156/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-20156
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-20156
- OSV: https://osv.dev/vulnerability/CVE-2018-20156

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-20156/
Summaries are generated and may contain mistakes; the official description above is the record.