Chamilo is a learning management system. Prior to version 1.11.30, a stored cross-site scripting (XSS) vulnerability exists in the session_category_add.php script. The vulnerability is caused by improper sanitization of the Category Name field, allowing privileged users to inject persistent JavaScript payloads. The injected script is later executed when accessing add_many_sessions_to_category.php, potentially compromising administrative sessions. This issue has been patched in version 1.11.30.