■■■■■ Researchers disclosed two new attack techniques that allow modifying visible content on certified PDF documents without invalidating the digital signature.
https://web-in-security.blogspot.com/2021/05/attacks-on-pdf-certification.html
https://securityaffairs.co/wordpress/118404/hacking/altering-signed-pdf-documents.html
https://t.me/cKure/8237