The ReadMNGImage function in coders/png.c in GraphicsMagick 1.3.26 has an out-of-order CloseBlob call, resulting in a use-after-free via a crafted file.
http://hg.code.sf.net/p/graphicsmagick/code/rev/d0a76868ca37
https://blogs.gentoo.org/ago/2017/07/12/graphicsmagick-use-after-free-in-closeblob-blob-c/
https://lists.debian.org/debian-lts-announce/2018/08/msg00002.html
Source: MITRE
Published: 2017-07-18
Updated: 2018-10-18
Type: CWE-416
Base Score: 6.8
Vector: AV:N/AC:M/Au:N/C:P/I:P/A:P
Impact Score: 6.4
Exploitability Score: 8.6
Severity: MEDIUM
Base Score: 8.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 2.8
Severity: HIGH