PDFs can also have file attachments. https://helpx.adobe.com/acrobat/using/links-attachments-pdfs.html https://helpx.adobe.com/acrobat/using/links-attachments-

PDFs can also have file attachments. https://helpx.adobe.com/acrobat/using/links-attachments-pdfs.html https://helpx.adobe.com/acrobat/using/links-attachments-pdfs... The official documentation also seems to recognize those as a security risk :) https://helpx.adobe.com/acrobat/using/attachments-security-risks-reader-acrobat.html https://helpx.adobe.com/acrobat/using/attachments-security-r...