CVE-2020-27780: pam: authentication bypass when the user doesn't exist and root password is blank

Severity: Critical

CVSS Score: 9.8

A flaw was found in Linux-Pam in versions prior to 1.5.1 in the way it handle empty passwords for non-existing users. When the user doesn't exist PAM try to authenticate with root and in the case of an empty password it successfully authenticate.