The Tutor LMS WordPress plugin before 3.9.13 does not verify ownership of the targeted quiz attempt before writing to it, allowing authenticated users with subscriber-level access and above to modify and force-complete other students' quiz attempts, overwriting their recorded marks and pass/fail result.
https://wpscan.com/vulnerability/ca99ea35-4bf8-4dc8-a817-79fb9fa1c5bd/