# CVE-2021-23394: Remote Code Execution (RCE)

> Attackers can achieve remote code execution by uploading malicious .phar files if the server is configured to parse them as PHP.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/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:** Yes
- **Published:** 13 Jun 2021
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-qm58-cvvm-c5qr, SNYK-PHP-STUDIO42ELFINDER-1290554

## What is CVE-2021-23394?

CVE-2021-23394 is a high-severity vulnerability in studio-42/elfinder, published on 13 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The package studio-42/elfinder before 2.1.58 are vulnerable to Remote Code Execution (RCE) via execution of PHP code in a .phar file. NOTE: This only applies if the server parses .phar files as PHP.

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

## Which versions are affected by CVE-2021-23394?

2 open source packages ship an affected version, including studio-42/elfinder. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `studio-42/elfinder` | Packagist | All versions | 2.1.58 |
| `studio-42/elfinder` | Packagist | All versions | 2.1.58 |

Products: Std42 Elfinder.

## How do I fix CVE-2021-23394?

Upgrade studio-42/elfinder to 2.1.58 or later.

## Is CVE-2021-23394 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-23394 exists.

Public exploit code:

- Docker container to setup a vulnerable elfinder version on both nginx and apache servers. Can be used to test vulnerability POC (github_poc): https://github.com/0xnemian/CVE-2021-23394
- elFinder < 2.1.58 - Remote Code Execution (nuclei): http/cves/2021/CVE-2021-23394.yaml

## Other vulnerabilities in studio-42/elfinder

- [CVE-2023-52044](https://insights.sbomify.com/CVE-2023-52044/): File upload in n/a (critical 9.8)
- [CVE-2024-38909](https://insights.sbomify.com/CVE-2024-38909/): Studio 42 elFinder vulnerable to Incorrect Access Control (critical 9.8)
- [CVE-2022-27115](https://insights.sbomify.com/CVE-2022-27115/): RCE in Studio-42 elFinder on Windows before 2.1.61 (critical 9.8)
- [CVE-2021-43421](https://insights.sbomify.com/CVE-2021-43421/): elFinder Unrestricted File Upload vulnerability (critical 9.8)
- [CVE-2021-32682](https://insights.sbomify.com/CVE-2021-32682/): Multiple vulnerabilities leading to RCE (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-23394 and fix it if it is affected.

What it is: CVE-2021-23394 is a high-severity vulnerability in studio-42/elfinder, published on 13 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-23394 exists.

Affected packages and fixed versions:
- studio-42/elfinder (Packagist): affected all versions; fixed in 2.1.58
- studio-42/elfinder (Packagist): affected all versions; fixed in 2.1.58

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-2021-23394/ (Markdown: https://insights.sbomify.com/CVE-2021-23394/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-23394
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-23394
- OSV: https://osv.dev/vulnerability/CVE-2021-23394

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-23394/
Summaries are generated and may contain mistakes; the official description above is the record.