The (1) core_enrol_get_course_enrolment_methods and (2) enrol_self_get_instance_info web services in Moodle through 2.6.11, 2.7.x before 2.7.12, 2.8.x before 2.8.10, 2.9.x before 2.9.4, and 3.0.x before 3.0.2 do not consider the moodle/course:viewhiddencourses capability, which allows remote authenticated users to obtain sensitive information via a web-service request.
https://moodle.org/mod/forum/discuss.php?d=326205
http://www.securitytracker.com/id/1034694
http://www.openwall.com/lists/oss-security/2016/01/18/1
http://lists.fedoraproject.org/pipermail/package-announce/2016-January/176436.html
http://lists.fedoraproject.org/pipermail/package-announce/2016-February/176502.html
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-52072