RubyGems is vulnerable to input validation errors. A remote, unauthenticated attacker could create a specially crafted RubyGem that, when installed by the target user, will allow the attacker to overwrite arbitrary files on the target system.
blog.rubygems.org/2017/08/27/2.6.13-released.html
www.securityfocus.com/bid/100580
www.securitytracker.com/id/1039249
access.redhat.com/errata/RHSA-2017:3485
access.redhat.com/errata/RHSA-2018:0378
access.redhat.com/errata/RHSA-2018:0583
access.redhat.com/errata/RHSA-2018:0585
access.redhat.com/security/updates/classification/#moderate
bugzilla.redhat.com/show_bug.cgi?id=1506785
github.com/rubygems/rubygems/commit/ad5c0a53a86ca5b218c7976765c0365b91d22cb2
hackerone.com/reports/243156
lists.debian.org/debian-lts-announce/2018/07/msg00012.html
security.gentoo.org/glsa/201710-01
usn.ubuntu.com/3553-1/
usn.ubuntu.com/3685-1/
www.debian.org/security/2017/dsa-3966
www.exploit-db.com/exploits/42611/