PT-2026-29325 · Oretnom23 · Alton Management System

Meifukun · Published 2026-03-31 · Updated 2026-03-31 · CVE-2026-30521

NVD

CVSS v3.1

6.5

Medium

Base vector

AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

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.

Exploit

Fix

Weakness Enumeration

CWE-602

Related Identifiers

CVE-2026-30521

Affected Products

Alton Management System

References · 2

• 🔥 https://github.com/meifukun/Web-Security-PoCs/blob/main/Loan-Management-System/BusinessLogic-LoanPlan-NegativeInterest.md · Exploit
• https://nvd.nist.gov/vuln/detail/CVE-2026-30521 · Security Note