# CVE-2026-33737: Chamilo LMS has an XML External Entity (XXE) Injection

> An attacker can read arbitrary server files via XML External Entity injection in Chamilo LMS due to unsafe XML parsing.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **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-c4ww-qgf2-v89j

## What is CVE-2026-33737?

CVE-2026-33737 is a medium-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 and 2.0.0-RC.3, multiple files use simplexml_load_string() without XXE protection. With LIBXML_NOENT flag, arbitrary server files can be read. This vulnerability is fixed in 1.11.38 and 2.0.0-RC.3.

Weakness: CWE-611 (Improper Restriction of XML External Entity Reference)

## Which versions are affected by CVE-2026-33737?

It affects 1 product.


Products: Chamilo Chamilo Lms.

## How do I fix CVE-2026-33737?

No fix has been published for CVE-2026-33737 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-33737 being exploited?

There is no known exploitation of CVE-2026-33737 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-2026-33737 and fix it if it is affected.

What it is: CVE-2026-33737 is a medium-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-2026-33737 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-2026-33737/ (Markdown: https://insights.sbomify.com/CVE-2026-33737/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-33737
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-33737
- OSV: https://osv.dev/vulnerability/CVE-2026-33737

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-33737/
Summaries are generated and may contain mistakes; the official description above is the record.