The Basic authentication code in WEBrick library in Ruby before 2.2.8, 2.3.x before 2.3.5, and 2.4.x through 2.4.1 allows remote attackers to inject terminal emulator escape sequences into its log and possibly execute arbitrary commands via a crafted user name.
https://github.com/advisories/GHSA-369m-2gv6-mw28
https://www.ruby-lang.org/en/news/2017/09/14/ruby-2-3-5-released/
https://www.ruby-lang.org/en/news/2017/09/14/ruby-2-2-8-released/
https://www.debian.org/security/2017/dsa-4031
https://usn.ubuntu.com/3685-1/
https://usn.ubuntu.com/3528-1/
https://security.gentoo.org/glsa/201710-18
https://lists.debian.org/debian-lts-announce/2018/07/msg00012.html
https://access.redhat.com/errata/RHSA-2018:0585
https://access.redhat.com/errata/RHSA-2018:0583
https://access.redhat.com/errata/RHSA-2018:0378