Acrobat Reader DC versions versions 2020.013.20074 (and earlier), 2020.001.30018 (and earlier) and 2017.011.30188 (and earlier) are missing support for an integrity check. An unauthenticated attacker would have the ability to completely manipulate data in a certified PDF without invalidating the original certification. Exploitation of this issue requires user interaction in that a victim must open the tampered file.