The wiki component in Moodle through 2.6.11, 2.7.x before 2.7.10, 2.8.x before 2.8.8, and 2.9.x before 2.9.2 does not consider the mod/wiki:managefiles capability before authorizing file management, which allows remote authenticated users to delete arbitrary files by using a manage-files button in a text editor.
https://moodle.org/mod/forum/discuss.php?d=320289
http://www.securitytracker.com/id/1033619
http://www.openwall.com/lists/oss-security/2015/09/21/1
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-48371