Cross-site scripting (XSS) vulnerability in cohort/edit_form.php in Moodle 2.0.x before 2.0.10, 2.1.x before 2.1.7, 2.2.x before 2.2.4, and 2.3.x before 2.3.1 allows remote authenticated administrators to inject arbitrary web script or HTML via the idnumber field.  NOTE: this vulnerability exists because of an incorrect fix for CVE-2012-2365.