CVE-2021-39857
Adobe Acrobat Reader DC add-on for Internet Explorer versions 2021.005.20060 (and earlier), 2020.004.30006 (and earlier) and 2017.011.30199 (and earlier) are affected by an Information Disclosure vulnerability. An unauthenticated attacker could leverage this vulnerability to check for existence of local files. Exploitation of this issue requires user interaction in that a victim must visit an attacker controlled web page.
Source: CVE-2021-39857