HIGH
Ruby before 2.4.3 allows Net::FTP command injection. Net::FTP#get, getbinaryfile, gettextfile, put, putbinaryfile, and puttextfile use Kernel#open to open a local file. If the localfile argument starts with the "|" pipe character, the command following the pipe character is executed. The default value of localfile is File.basename(remotefile), so malicious FTP servers could cause arbitrary command execution.
http://www.securityfocus.com/bid/102204
http://www.securitytracker.com/id/1042004
https://access.redhat.com/errata/RHSA-2018:0378
https://access.redhat.com/errata/RHSA-2018:0583
https://access.redhat.com/errata/RHSA-2018:0584
https://access.redhat.com/errata/RHSA-2018:0585
https://lists.debian.org/debian-lts-announce/2017/12/msg00024.html
https://lists.debian.org/debian-lts-announce/2017/12/msg00025.html
https://lists.debian.org/debian-lts-announce/2018/07/msg00012.html
https://www.debian.org/security/2018/dsa-4259
https://www.exploit-db.com/exploits/43381/
https://www.ruby-lang.org/en/news/2017/12/14/net-ftp-command-injection-cve-2017-17405/
https://www.ruby-lang.org/en/news/2017/12/14/ruby-2-4-3-released/
Source: MITRE
Published: 2017-12-15
Updated: 2019-03-14
Type: CWE-78
Base Score: 9.3
Vector: AV:N/AC:M/Au:N/C:C/I:C/A:C
Impact Score: 10
Exploitability Score: 8.6
Severity: HIGH
Base Score: 8.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Impact Score: 5.9
Exploitability Score: 2.8
Severity: HIGH