Summary:

The contract is designed such that, at the end of each school session, only 40% of the collected school fees should be paid out—5% to the principal and 35% shared among all teachers. The remaining 60% should remain in the bursary for future use. However, the current implementation mistakenly pays the entire 35% share to each teacher, rather than distributing it collectively across all teachers. This results in overpayment and leads to rapid exhaustion of the bursary fund.

Vulnerability Details:

Expected Behavior (as per documentation):

• Principal: Receives 5% of the bursary.

• Teachers: Collectively receive 35% of the bursary (shared equally).

• Bursary: 60% should remain after payouts.

Current Buggy Behavior in Code:

uint256 teacherShare = (bursary * 35) / 100;

for (uint i = 0; i < listOfTeachers.length; i++) {

usdc.transfer(listOfTeachers[i], teacherShare); // 🔴 Bug: Full 35% given to each teacher

}

This implementation erroneously pays each teacher 35% of the bursary, leading to:

• Overpayment: If there are 3 teachers, 105% of the bursary is paid.

• Bursary Depletion: Contract funds are exhausted prematurely.

• Injustice: Early teachers get unfairly high wages, breaking the reward structure.

Impact:

Critical financial flaw: Bursary will be drained rapidly, leaving no funds for future sessions.

Systemic failure: Future session upgrades or withdrawals may fail due to insufficient funds.

Unequal compensation: Teachers in earlier sessions get disproportionately higher rewards.

Tools Used :

Mannual Review

Recommendations:

Fix the payout logic to divide the 35% teacher share equally among all teachers:

uint256 totalTeacherShare = (bursary * 35) / 100;

uint256 perTeacherShare = totalTeacherShare / listOfTeachers.length;

for (uint256 i = 0; i < listOfTeachers.length; i++) {

usdc.transfer(listOfTeachers[i], perTeacherShare);

}

Additional Suggestions:

Add unit tests to confirm:

Principal receives exactly 5%.

Teachers collectively receive 35%.

60% of the bursary remains after distribution.