Acrobat Reader DC versions versions 2020.013.20074 (and earlier), 2020.001.30018 (and earlier) and 2017.011.30188 (and earlier) are affected by an improper access control vulnerability. An unauthenticated attacker could leverage this vulnerability to elevate privileges in the context of the current user.
https://helpx.adobe.com/security/products/acrobat/apsb21-09.html