# CVE-2018-6383: File upload in n/a

> Authenticated admins or editors can execute arbitrary PHP code by uploading files with .pht or .phar extensions due to an incomplete forbidden types list.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Jan 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-4cjq-7wr8-ccw5

## What is CVE-2018-6383?

CVE-2018-6383 is a high-severity vulnerability in n/a, published on 29 Jan 2018. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Monstra CMS through 3.0.4 has an incomplete "forbidden types" list that excludes .php (and similar) file extensions but not the .pht or .phar extension, which allows remote authenticated Admins or Editors to execute arbitrary PHP code by uploading a file, a different vulnerability than CVE-2017-18048.

Weakness: CWE-184 (Incomplete List of Disallowed Inputs)

## Which versions are affected by CVE-2018-6383?

It affects 1 product.


Products: Monstra Monstra.

## How do I fix CVE-2018-6383?

No fix has been published for CVE-2018-6383 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-6383 being exploited?

There is no known exploitation of CVE-2018-6383 in the wild and no public exploit code.

Public exploit code:

- Monstra CMS 3.0.4 - Remote Code Execution (Authenticated) (exploitdb)

## Other vulnerabilities in n/a

- [CVE-2021-40940](https://insights.sbomify.com/CVE-2021-40940/): File upload in n/a (critical 9.8)
- [CVE-2021-36548](https://insights.sbomify.com/CVE-2021-36548/): File upload in n/a (critical 9.8)
- [CVE-2020-25414](https://insights.sbomify.com/CVE-2020-25414/): Code injection in n/a (critical 9.8)
- [CVE-2020-13384](https://insights.sbomify.com/CVE-2020-13384/): File upload in n/a (high 8.8)
- [CVE-2018-16608](https://insights.sbomify.com/CVE-2018-16608/): Missing authorization in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-6383 and fix it if it is affected.

What it is: CVE-2018-6383 is a high-severity vulnerability in n/a, published on 29 Jan 2018. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-6383 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-2018-6383/ (Markdown: https://insights.sbomify.com/CVE-2018-6383/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-6383
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-6383
- OSV: https://osv.dev/vulnerability/CVE-2018-6383

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-6383/
Summaries are generated and may contain mistakes; the official description above is the record.