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.

Affected: Ubuntu:14.04:LTS: ruby1.9.1, Ubuntu:14.04:LTS: ruby2.0, Ubuntu:16.04:LTS: ruby2.3

It was discovered that Ruby allows FTP command injection. An attacker could use this to cause arbitrary command execution.