The FoFiType1C::cvtGlyph function in fofi/FoFiType1C.cc in Poppler through 0.64.0 allows remote attackers to cause a denial of service (infinite recursion) via a crafted PDF file, as demonstrated by pdftops.
access.redhat.com/errata/RHBA-2019:0327
access.redhat.com/errata/RHSA-2018:3140
access.redhat.com/errata/RHSA-2018:3505
bugzilla.freedesktop.org/show_bug.cgi?id=103238
lists.debian.org/debian-lts-announce/2018/10/msg00024.html
lists.debian.org/debian-lts-announce/2020/07/msg00018.html
usn.ubuntu.com/3647-1/