Arbitrary file upload in Chamilo Chamilo-Lms

CVE-2026-33704

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.

Vulnerability class: Unrestricted File Upload

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L.

EPSS exploit prediction

EPSS: 0.008 (53.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 53.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-33704: held from 0.004 to 0.008.

EPSS over last 30 days · oldest: 0.004 · newest: 0.008 · change: +0.003

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-33704?
CVE-2026-33704 is a high-severity vulnerability in Chamilo Chamilo-Lms, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 7.1/10. Published 2026-04-10.
How severe is CVE-2026-33704?
High severity. CVSS v3 base score is 7.1 out of 10.