Salt before 2015.5.10 and 2015.8.x before 2015.8.8, when PAM external authentication is enabled, allows attackers to bypass the configured authentication service by passing an alternate service with a command sent to LocalClient.
https://docs.saltstack.com/en/latest/topics/releases/2015.8.8.html
https://docs.saltstack.com/en/latest/topics/releases/2015.5.10.html