CVE-2014-3552: Improper Authentication

The Shibboleth authentication plugin in auth/shibboleth/index.php in Moodle through 2.3.11, 2.4.x before 2.4.11, and 2.5.x before 2.5.7 does not check whether a session ID is empty, which allows remote authenticated users to hijack sessions via crafted plugin interaction...