CVE-2026-30521

State: Published
Severity: 6.5 Medium
Published: Mar 31, 2026
Updated: Apr 2, 2026
Reserved: Mar 4, 2026

Description

A Business Logic vulnerability exists in SourceCodester Loan Management System v1.0 due to improper server-side validation. The application allows administrators to create "Loan Plans" with specific interest rates. While the frontend interface prevents users from entering negative numbers, this constraint is not enforced on the backend. An authenticated attacker can bypass the client-side restriction by manipulating the HTTP POST request to submit a negative value for the interest_percentage. This results in the creation of loan plans with negative interest rates.

Scores

CVSS	Score	Vector	Source
3.1	6.5 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N	CISA-ADP

Weaknesses

CWE-602 Client-Side Enforcement of Server-Side Security

Affected Products

Product	Versions
n/an/a	n/aAffected

References

https://github.com/meifukun/Web-Security-PoCs/blob/main/Loan-Management-System/BusinessLogic-LoanPlan-NegativeInterest.md

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