Summary:

The giveReview function in the LevelOne contract fails to increment the reviewCount mapping after a review is given. This allows teachers to submit unlimited reviews for a student, breaking the intended weekly review constraint and session grading logic.

Vulnerability Details:

The function contains a require

require(reviewCount[_student] < 5, "Student review count exceeded!");

However, the reviewCount[_student] is never incremented after a review is submitted. As a result, this check always passes, because the counter remains at its default value of 0.

Impact:

Anyone with the onlyTeacher role can exploit this to give multiple reviews.

Tools Used:

Mannual Review

Recommendations:

lastReviewTime[_student] = block.timestamp;

reviewCount[_student] += 1;

emit ReviewGiven(_student, review, studentScore[_student]);