The link to update all installed language packs did not include the necessary token to prevent a CSRF risk.
https://moodle.org/mod/forum/discuss.php?d=455638
https://bugzilla.redhat.com/show_bug.cgi?id=2264098
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-54749