Moodle through 2.6.11, 2.7.x before 2.7.11, 2.8.x before 2.8.9, and 2.9.x before 2.9.3 does not consider the moodle/badges:viewbadges capability, which allows remote authenticated users to obtain sensitive badge information via a request involving (1) badges/overview.php or (2) badges/view.php.
https://moodle.org/mod/forum/discuss.php?d=323235
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-51684