Acrobat Reader DC versions 2021.005.20060 (and earlier), 2020.004.30006 (and earlier) and 2017.011.30199 (and earlier) are affected by an Uncontrolled Search Path Element vulnerability. A local attacker with non-administrative privileges can plant a malicious DLL to achieve arbitrary code execution in the context of the current user via DLL hijacking. Exploitation of this issue requires user interaction.
https://helpx.adobe.com/security/products/acrobat/apsb21-55.html