Acrobat Pro DC versions 2021.005.20060 (and earlier), 2020.004.30006 (and earlier) and 2017.011.30199 (and earlier) are affected by a Null pointer dereference vulnerability. An unauthenticated attacker could leverage this vulnerability to disclose sensitive user memory. Exploitation of this issue requires user interaction in that a victim must open a malicious file.
https://helpx.adobe.com/security/products/acrobat/apsb21-55.html