An issue was discovered in VirtoSoftware Virto Bulk File Download 5.5.44 for SharePoint 2019. The Virto.SharePoint.FileDownloader/Api/Download.ashx isCompleted method allows arbitrary file download and deletion via absolute path traversal in the path parameter.
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.