There is an invalid free in the MagickFree function in magick/memory.c in GraphicsMagick 1.3.26 that will lead to a remote denial of service attack.
http://hg.graphicsmagick.org/hg/GraphicsMagick/rev/3db9449e3d6a/
http://openwall.com/lists/oss-security/2017/08/29/4
http://www.securityfocus.com/bid/100518
https://bugs.debian.org/878511
https://bugzilla.redhat.com/show_bug.cgi?id=1484196
https://lists.debian.org/debian-lts-announce/2018/08/msg00002.html
Source: MITRE
Published: 2017-08-29
Updated: 2019-06-30
Type: CWE-416
Base Score: 4.3
Vector: AV:N/AC:M/Au:N/C:N/I:N/A:P
Impact Score: 2.9
Exploitability Score: 8.6
Severity: MEDIUM
Base Score: 6.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Impact Score: 3.6
Exploitability Score: 2.8
Severity: MEDIUM