A flaw was found in moodle where global search results could include author information on some activities where a user may not otherwise have access to it.
https://moodle.org/mod/forum/discuss.php?d=434580
https://bugzilla.redhat.com/show_bug.cgi?id=2083592
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-71623