Adobe also has critical Reader and Flash updates this month & users should promptly get up-to-date (esp. as prompted by automated update notices)

Adobe December 2018 Security Update Fixes Reader, Acrobat

https://helpx.adobe.com/security/products/acrobat/apsb18-41.html

Adobe has patched 87 vulnerabilities for Acrobat and Reader in its December Patch Tuesday update, including a slew of critical flaws that would allow arbitrary code-execution.  The scheduled update comes less than a week after Adobe released several out-of-band fixes for Flash Player, including a critical vulnerability (CVE-2018-15982) that it said is being exploited in the wild. That’s a use-after-free flaw enabling arbitrary code-execution in Flash.