RubyGems version Ruby 2.2 series: 2.2.9 and earlier, Ruby 2.3 series: 2.3.6 and earlier, Ruby 2.4 series: 2.4.3 and earlier, Ruby 2.5 series: 2.5.0 and earlier, prior to trunk revision 62422 contains a Directory Traversal vulnerability in gem installation that can result in the gem writing to arbitrary filesystem locations during installation. This attack appears to be exploitable via installation of a malicious gem. This vulnerability is fixed in 2.7.6.
blog.rubygems.org/2018/02/15/2.7.6-released.html
lists.opensuse.org/opensuse-security-announce/2019-07/msg00036.html
access.redhat.com/errata/RHSA-2018:3729
access.redhat.com/errata/RHSA-2018:3730
access.redhat.com/errata/RHSA-2018:3731
access.redhat.com/errata/RHSA-2019:2028
access.redhat.com/errata/RHSA-2020:0542
access.redhat.com/errata/RHSA-2020:0591
access.redhat.com/errata/RHSA-2020:0663
bugs.debian.org/cgi-bin/bugreport.cgi?bug=895778
github.com/jruby/jruby/commit/0b06b48ab4432237ce5fc1bef47f2c6bcf7843f7
github.com/rubygems/rubygems/commit/5971b486d4dbb2bad5d3445b3801c456eb0ce183
github.com/rubygems/rubygems/commit/666ef793cad42eed96f7aee1cdf77865db921099
github.com/rubygems/rubygems/commit/f83f911e19e27cbac1ccce7471d96642241dd759
lists.debian.org/debian-lts-announce/2018/07/msg00012.html
nvd.nist.gov/vuln/detail/CVE-2018-1000079
security-tracker.debian.org/tracker/CVE-2018-1000079
usn.ubuntu.com/3621-1
www.debian.org/security/2018/dsa-4219
www.debian.org/security/2018/dsa-4259