Moodle 2.x through 2.1.10, 2.2.x before 2.2.8, 2.3.x before 2.3.5, and 2.4.x before 2.4.2 allows remote authenticated administrators to obtain sensitive information from the external repositories of arbitrary users by leveraging the login_as feature.
https://moodle.org/mod/forum/discuss.php?d=225347
http://openwall.com/lists/oss-security/2013/03/25/2
http://lists.fedoraproject.org/pipermail/package-announce/2013-April/101358.html
http://lists.fedoraproject.org/pipermail/package-announce/2013-April/101310.html
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-36426