MEDIUM
RubyGems version 2.6.12 and earlier is vulnerable to a DNS hijacking vulnerability that allows a MITM attacker to force the RubyGems client to download and install gems from a server that the attacker controls.
http://blog.rubygems.org/2017/08/27/2.6.13-released.html
http://www.securityfocus.com/bid/100586
http://www.securitytracker.com/id/1039249
https://access.redhat.com/errata/RHSA-2017:3485
https://access.redhat.com/errata/RHSA-2018:0378
https://access.redhat.com/errata/RHSA-2018:0583
https://access.redhat.com/errata/RHSA-2018:0585
https://github.com/rubygems/rubygems/commit/8d91516fb7037ecfb27622f605dc40245e0f8d32
https://hackerone.com/reports/218088
https://lists.debian.org/debian-lts-announce/2018/07/msg00012.html
https://security.gentoo.org/glsa/201710-01
https://usn.ubuntu.com/3553-1/
Source: MITRE
Published: 2017-08-31
Updated: 2019-05-13
Type: CWE-284
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: 8.1
Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 2.2
Severity: HIGH