Improper sanitisation in `main/inc/lib/fileUpload.lib.php` in Chamilo LMS <= v1.11.20 on Windows and Apache installations allows unauthenticated attackers to bypass file upload security protections and obtain remote code execution via uploading of `.htaccess` file. This vulnerability may be exploited by privileged attackers or chained with unauthenticated arbitrary file write vulnerabilities, such as CVE-2023-3533, to achieve remote code execution.
https://starlabs.sg/advisories/23/23-3545/
https://github.com/chamilo/chamilo-lms/commit/dc7bfce429fbd843a95a57c184b6992c4d709549