Cross-site scripting (XSS) vulnerability in the get_description function in lib/classes/event/user_login_failed.php in Moodle 2.7.x before 2.7.1 allows remote attackers to inject arbitrary web script or HTML via a crafted username that is improperly handled during the logging of an invalid login attempt.
Improper Neutralization of Input During Web Page Generation The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.