# CVE-2021-28998: File upload in n/a

> Authenticated attackers can upload malicious phar files to execute arbitrary code on CMS Made Simple installations.

- **Severity:** High 7.2 (`CVSS:3.1/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:** 8 May 2023
- **Updated:** 29 Jan 2025
- **Also known as:** GHSA-h6jm-ghq6-38cg

## What is CVE-2021-28998?

CVE-2021-28998 is a high-severity vulnerability in Cmsmadesimple Cms Made Simple, published on 8 May 2023. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

File upload vulnerability in CMS Made Simple through 2.2.15 allows remote authenticated attackers to gain a webshell via a crafted phar file.

Weakness: CWE-434 (Unrestricted Upload of File with Dangerous Type)

## Which versions are affected by CVE-2021-28998?

It affects 1 product.


Products: Cmsmadesimple Cms Made Simple.

## How do I fix CVE-2021-28998?

No fix has been published for CVE-2021-28998 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-28998 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-28998 exists.

## Other vulnerabilities in Cmsmadesimple Cms Made Simple

- [CVE-2010-4663](https://insights.sbomify.com/CVE-2010-4663/): Other in n/a (critical 10.0)
- [CVE-2024-1527](https://insights.sbomify.com/CVE-2024-1527/): Unrestricted Upload of File with Dangerous Type in CMS Made Simple (critical 9.8)
- [CVE-2018-10081](https://insights.sbomify.com/CVE-2018-10081/): Auth bypass in n/a (critical 9.8)
- [CVE-2018-10085](https://insights.sbomify.com/CVE-2018-10085/): Deserialization in n/a (critical 9.8)
- [CVE-2017-1000453](https://insights.sbomify.com/CVE-2017-1000453/): Code injection in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-28998 and fix it if it is affected.

What it is: CVE-2021-28998 is a high-severity vulnerability in Cmsmadesimple Cms Made Simple, published on 8 May 2023. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-28998 exists.

Affected product: Cmsmadesimple Cms Made Simple. 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-2021-28998/ (Markdown: https://insights.sbomify.com/CVE-2021-28998/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-28998
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-28998
- OSV: https://osv.dev/vulnerability/CVE-2021-28998

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-28998/
Summaries are generated and may contain mistakes; the official description above is the record.