Use-after-free vulnerability in Decoder.cpp in libpgf before 6.15.32.
https://usn.ubuntu.com/4554-1/
https://sourceforge.net/p/libpgf/code/HEAD/tree/trunk/libpgf/INSTALL
https://sourceforge.net/p/libpgf/code/148/
https://sourceforge.net/p/libpgf/code/147/
https://security-tracker.debian.org/tracker/CVE-2015-6673/
https://lists.debian.org/debian-lts-announce/2019/12/msg00017.html