GraphicsMagick 1.3.26 has a NULL pointer dereference in the WritePCLImage() function in coders/pcl.c during writes of monochrome images.
https://lists.debian.org/debian-lts-announce/2018/08/msg00002.html
https://usn.ubuntu.com/4206-1/
https://www.debian.org/security/2018/dsa-4321
Source: Mitre, NVD
Published: 2017-07-26
Base Score: 7.5
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P
Severity: High
Base Score: 9.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity: Critical