RosarioSIS before 12.9.1 contains a missing authorization vulnerability that allows authenticated teachers to write records for students outside their course period by supplying arbitrary student IDs. Attackers can modify the st_arr, values, or attendance POST arrays in MakeReferral.php, EnterEligibility.php, InputFinalGrades.php, and TakeAttendance.php to create referrals, eligibility codes, attendance and final grades for any student in the school.