Improper Neutralization of Special Elements used in a Command ('Command Injection')
Ansible before version 2.2.0 fails to properly sanitize fact variables sent from the Ansible controller. An attacker with the ability to create special variables on the controller could execute arbitrary commands on Ansible clients as the user Ansible runs as.
CWE-77 - Command Injection
A command injection attack involves injecting an operating system command through the data input, which gets executed on the host operating system with the privileges of the victimized application. The impact of a command injection attack may range from loss of data confidentiality and integrity to unauthorized remote access to the hosting system. The attack may cause serious data breaches and system takeover.