CVE-2026-30521Public exploitNetwork attack vector

Financial data corruption via unchecked negative interest

Published Mar 31, 2026 · Updated Mar 31, 2026

Business logic error in SourceCodester Loan Management System 1.0 allows remote authenticated users to create negative-rate loan plans. The ajax.php?action=save_plan endpoint accepts a negative interest_percentage value from a direct HTTP POST because the backend omits the range check enforced by the interface. Administrator access is required, and successful exploitation stores a loan plan whose negative rate corrupts financial calculations and terms.

CVSS severity6.5
Medium
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Business logic error in SourceCodester Loan Management System 1.0 allows remote authenticated users to create negative-rate loan plans. The ajax.php?action=save_plan endpoint accepts a negative interest_percentage value from a direct HTTP POST because the backend omits the range check enforced by the interface. Administrator access is required, and successful exploitation stores a loan plan whose negative rate corrupts financial calculations and terms.

The record

CVE
CVE-2026-30521
Published
Mar 31, 2026
Updated
Mar 31, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-602, T1565.001
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Mar 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 31, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
6.5NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-602Client-Side Enforcement of Server-Side Security
T1565.001Stored Data Manipulation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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