Describe CVE-2011-4593.
What is CVE-2011-4593?
Moodle 1.9.x before 1.9.15, 2.0.x before 2.0.6, and 2.1.x before 2.1.3 does not properly handle user/action_redir group messages, which allows remote authenticated users to discover e-mail addresses by visiting the messaging interface..