notes/edit.php in Moodle 1.9.x through 1.9.19, 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 users to reassign notes via a modified (1) userid or (2) courseid field.
https://moodle.org/mod/forum/discuss.php?d=225346
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-37411