Multiple cross-site request forgery (CSRF) vulnerabilities in the lesson module in Moodle through 2.6.11, 2.7.x before 2.7.11, 2.8.x before 2.8.9, and 2.9.x before 2.9.3 allow remote attackers to hijack the authentication of arbitrary users for requests to (1) mod/lesson/mediafile.php or (2) mod/lesson/view.php.
git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-48109
github.com/moodle/moodle/commit/541c5b8552e0162010d0259c90a04eb63e875958
github.com/moodle/moodle/commit/817cae1ac7ca748ba368439a40ef67d555774485
github.com/moodle/moodle/commit/dcb42c9ed13b0c0ec2dde22b62ef69772d7725e6
github.com/moodle/moodle/commit/f75333766c7295932baa72a9dbe9542baf14e107
moodle.org/mod/forum/discuss.php?d=323233
nvd.nist.gov/vuln/detail/CVE-2015-5338