PdfDing: Password-protected share bypass via direct serve endpoint

PdfDing is a selfhosted PDF manager, viewer and editor offering a seamless user experience on multiple devices. Prior to version 1.7.0, an access-control vulnerability allows unauthenticated users to retrieve password-protected shared PDFs by directly calling the file-serving endpoint without completing the password verification flow. This results in unauthorized access to confidential documents that users expected to be protected by a shared-link password. This issue has been patched in version 1.7.0.