Moodle before 2.2.2 has a password and web services issue where when the user profile is updated the user password is reset if not specified.
https://security-tracker.debian.org/tracker/CVE-2012-1168
https://moodle.org/mod/forum/discuss.php?d=198622
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2012-1168
http://lists.fedoraproject.org/pipermail/package-announce/2012-May/081047.html
http://lists.fedoraproject.org/pipermail/package-announce/2012-May/080712.html
http://lists.fedoraproject.org/pipermail/package-announce/2012-April/078210.html
http://lists.fedoraproject.org/pipermail/package-announce/2012-April/078209.html
http://lists.fedoraproject.org/pipermail/package-announce/2012-April/077635.html