Moodle 2.0.x before 2.0.2 does not use the forceloginforprofiles setting for course-profiles access control, which makes it easier for remote attackers to obtain potentially sensitive information via vectors involving use of a search engine, as demonstrated by the search functionality of Google, Yahoo!, Wrensoft Zoom, MSN, Yandex, and AltaVista.
http://openwall.com/lists/oss-security/2011/11/14/1
http://moodle.org/mod/forum/discuss.php?d=170004
http://git.moodle.org/gw?p=moodle.git%3Ba=commit%3Bh=81b58cc227cf96a1cd2e002cc210b7b3e376fd17