enrol/index.php in Moodle 2.6.x before 2.6.3 does not check for the moodle/course:viewhiddencourses capability before listing hidden courses, which allows remote attackers to obtain sensitive name and summary information about these courses by leveraging the guest role and visiting a crafted URL.
git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-45126
openwall.com/lists/oss-security/2014/05/19/1
github.com/moodle/moodle
github.com/moodle/moodle/commit/eaea796e70f6630494d3772684604ab6e907f4ac
github.com/moodle/moodle/commit/fcf199e7a13e453bfe3855c6946e8357fcbdef92
moodle.org/mod/forum/discuss.php?d=260365
nvd.nist.gov/vuln/detail/CVE-2014-0217