What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-10 · updated 2026-10-26
• Weakness: CWE-434

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.

Affected products

• chamilo-lms: before 1.11.38 — fixed in 1.11.38

How to fix

Upgrade to a fixed version: chamilo-lms 1.11.38. Check the vendor advisory for mitigations.

References

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

Get alerted when CVE-2026-33704 or the next vulnerability affects your stack