Foxit Reader before 9.5, and PhantomPDF before 8.3.10 and 9.x before 9.5, has a proxyDoAction race condition that can cause a stack-based buffer overflow or an out-of-bounds read, a different issue than CVE-2018-20310 because of a different opcode.
https://www.foxitsoftware.com/support/security-bulletins.php