The identity-reporting implementations in mod/forum/renderer.php and mod/quiz/override_form.php in Moodle through 2.3.11, 2.4.x before 2.4.9, 2.5.x before 2.5.5, and 2.6.x before 2.6.2 do not properly restrict the display of e-mail addresses, which allows remote authenticated users to obtain sensitive information by using the (1) Forum or (2) Quiz module.
https://moodle.org/mod/forum/discuss.php?d=256421
http://openwall.com/lists/oss-security/2014/03/17/1
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-43916