An exploitable use-after-free vulnerability exists in the JavaScript engine of Foxit Software's PDF Reader, version 9.1.0.5096. A specially crafted PDF document can trigger a previously freed object in memory to be reused. An attacker needs to trick the user to open the malicious file to trigger.
https://www.foxitsoftware.com/support/security-bulletins.php
https://talosintelligence.com/vulnerability_reports/TALOS-2018-0607