Cross-site scripting (XSS) vulnerability in lib/filelib.php in Moodle 2.0.x before 2.0.9, 2.1.x before 2.1.6, and 2.2.x before 2.2.3 allows remote authenticated users to inject arbitrary web script or HTML via an assignment submission with zip compression, leading to text/html rendering during a "download all" action.
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.