Adobe Acrobat and Reader versions 2019.008.20081 and earlier, 2019.008.20080 and earlier, 2019.008.20081 and earlier, 2017.011.30106 and earlier version, 2017.011.30105 and earlier version, 2015.006.30457 and earlier, and 2015.006.30456 and earlier have a security bypass vulnerability. Successful exploitation could lead to information disclosure.
https://www.pdfa.org/recently-identified-pdf-digital-signature-vulnerabilities/
https://pdf-insecurity.org/signature/signature.html
https://pdf-insecurity.org/signature/evaluation_2018.html
https://helpx.adobe.com/security/products/acrobat/apsb18-41.html