In Poppler 0.68.0, the Parser::getObj() function in Parser.cc may cause infinite recursion via a crafted file. A remote attacker can leverage this for a DoS attack.
https://usn.ubuntu.com/3837-2/
https://usn.ubuntu.com/3837-1/
https://lists.debian.org/debian-lts-announce/2020/07/msg00018.html
https://lists.debian.org/debian-lts-announce/2018/12/msg00004.html
https://lists.debian.org/debian-lts-announce/2018/11/msg00040.html
https://lists.debian.org/debian-lts-announce/2018/10/msg00024.html