In ghostscript before version 9.50, the .buildfont1 procedure did not properly secure its privileged calls, enabling scripts to bypass `-dSAFER` restrictions. An attacker could abuse this flaw by creating a specially crafted PostScript file that could escalate privileges and access files outside of restricted areas.
https://security.gentoo.org/glsa/202004-03
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-10216
http://git.ghostscript.com/?p=ghostpdl.git%3Ba=commitdiff%3Bh=5b85ddd19