In Artifex Ghostscript through 9.25, the setpattern operator did not properly validate certain types. A specially crafted PostScript document could exploit this to crash Ghostscript or, possibly, execute arbitrary code in the context of the Ghostscript process. This is a type confusion issue because of failure to check whether the Implementation of a pattern dictionary was a structure type.
http://git.ghostscript.com/?p=ghostpdl.git;a=commitdiff;h=693baf02152119af6e6afd30bb8ec76d14f84bbf
http://www.securityfocus.com/bid/106278
https://access.redhat.com/errata/RHSA-2018:3834
https://bugs.ghostscript.com/show_bug.cgi?id=700141
https://lists.debian.org/debian-lts-announce/2018/12/msg00019.html
https://semmle.com/news/semmle-discovers-severe-vulnerability-ghostscript-postscript-pdf
Source: MITRE
Published: 2018-12-20
Updated: 2019-01-11
Type: CWE-704
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: 7.8
Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 1.8
Severity: HIGH