Medium severity · published Mar 31, 2026
CVE-2026-30521
A Business Logic vulnerability exists in SourceCodester Loan Management System v1.0 due to improper server-side validation
6.5
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 24% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LM
Loan Management System · Oretnom23
1.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-30521
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-30521
Exploit
https://github.com/meifukun/Web-Security-PoCs/blob/main/Loan-Management-System/BusinessLogic-LoanPlan-NegativeInterest.md
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