Multiple cross-site request forgery (CSRF) vulnerabilities in mod/assign/locallib.php in the Assignment subsystem in Moodle through 2.3.11, 2.4.x before 2.4.10, 2.5.x before 2.5.6, and 2.6.x before 2.6.3 allow remote attackers to hijack the authentication of teachers for quick-grading requests.