Exposure of Sensitive Information to an Unauthorized Actor
Moodle 2.1.x before 2.1.6 and 2.2.x before 2.2.3 allows remote authenticated users to obtain sensitive user information from hidden fields by leveraging the teacher role and navigating to "Enrolled users" under the Users Settings section.
CWE-200 - Information Exposure
An information exposure vulnerability is categorized as an information flow (IF) weakness, which can potentially allow unauthorized access to otherwise classified information in the application, such as confidential personal information (demographics, financials, health records, etc.), business secrets, and the application's internal environment.