Directory creation via unchecked traversal segments

Path traversal in FileRise before 3.19.0 allows remote authenticated users to create directories outside the upload root via folder names. FolderController::createFolder validates folderName as a whole string, then FolderModel::createFolder appends unchecked dot-dot segments and recursively creates the destination without containment checks. Exploitation requires a valid CSRF token and create or owner permission on the parent; directory creation is limited by web-server write permissions and does not directly write files or execute code.