Multiple open redirect vulnerabilities in Moodle 2.2.x before 2.2.7, 2.3.x before 2.3.4, and 2.4.x before 2.4.1 allow remote attackers to redirect users to arbitrary web sites and conduct phishing attacks via vectors related to (1) backup/backupfilesedit.php, (2) comment/comment_post.php, (3) course/switchrole.php, (4) mod/wiki/filesedit.php, (5) tag/coursetags_add.php, or (6) user/files.php.
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.