# CVE-2026-33704: Chamilo LMS Affected by Authenticated Arbitrary File Write via BigUpload endpoint

> Authenticated users can upload malicious files with .pht extensions to achieve remote code execution on Apache servers configured to process them as PHP.

- **Severity:** High 7.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L`)
- **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:** 10 Apr 2026
- **Updated:** 13 Apr 2026
- **Also known as:** GHSA-phfx-pwwg-945v

## What is CVE-2026-33704?

CVE-2026-33704 is a high-severity vulnerability in Chamilo Chamilo Lms, published on 10 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Chamilo LMS is a learning management system. Prior to 1.11.38, any authenticated user (including students) can write arbitrary content to files on the server via the BigUpload endpoint. The key parameter controls the filename and the raw POST body becomes the file content. While .php extensions are filtered to .phps, the .pht extension passes through unmodified. On Apache configurations where .pht is handled as PHP, this leads to Remote Code Execution. This vulnerability is fixed in 1.11.38.

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

## Which versions are affected by CVE-2026-33704?

It affects 1 product.


Products: Chamilo Chamilo Lms.

## How do I fix CVE-2026-33704?

No fix has been published for CVE-2026-33704 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-33704 being exploited?

There is no known exploitation of CVE-2026-33704 in the wild and no public exploit code.

## Other vulnerabilities in Chamilo Chamilo Lms

- [CVE-2025-50187](https://insights.sbomify.com/CVE-2025-50187/): Chamilo: Evaluation of untrusted user input leads to Remote Code Execution (critical 9.8)
- [CVE-2023-34944](https://insights.sbomify.com/CVE-2023-34944/): File upload in n/a (critical 9.8)
- [CVE-2022-27423](https://insights.sbomify.com/CVE-2022-27423/): SQL injection in n/a (critical 9.8)
- [CVE-2021-35414](https://insights.sbomify.com/CVE-2021-35414/): SQL injection in n/a (critical 9.8)
- [CVE-2019-13082](https://insights.sbomify.com/CVE-2019-13082/): File upload in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-33704 and fix it if it is affected.

What it is: CVE-2026-33704 is a high-severity vulnerability in Chamilo Chamilo Lms, published on 10 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-33704 in the wild and no public exploit code.

Affected product: Chamilo Chamilo Lms. 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-2026-33704/ (Markdown: https://insights.sbomify.com/CVE-2026-33704/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-33704
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-33704
- OSV: https://osv.dev/vulnerability/CVE-2026-33704

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-33704/
Summaries are generated and may contain mistakes; the official description above is the record.