VulnerabilityPublished 1 Apr 2026

CVE-2026-30522: Loan-Management-System · Client-Side Enforcement of Server-Side Security

Affects Loan-Management-SystemSource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 16% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 1 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
GitHubmeifukun/Loan-Management-System`pkg:github/meifukun/Loan-Management-System`Other threats	Affected =1.0	Fixed in–

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AI-suggested

To mitigate this vulnerability, organizations should implement strict server-side validation for all input fields, especially those affecting financial calculations such as penalty rates. Specifically, the backend must reject any negative values for the "Monthly Overdue Penalty" field regardless of client-side restrictions. Conduct a thorough code review and input validation audit to ensure no other fields are vulnerable to similar bypasses. Implement role-based access controls and monitor administrator activities to detect anomalous loan plan creations or modifications. Logging and alerting on unusual penalty rates can help identify exploitation attempts. Regularly update and patch the loan management system once a vendor fix or patch becomes available. Additionally, consider implementing multi-factor authentication for administrator accounts to reduce the risk of account compromise. Educate administrators about the risks of manipulating loan parameters and enforce strict operational procedures for loan plan management.

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 penalty rates for overdue payments. While the frontend interface prevents users from entering negative numbers in the "Monthly Overdue Penalty" field, 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 penalty_rate.

Impact

The primary impact of this vulnerability is on the integrity and financial accuracy of loan management operations. By submitting negative penalty rates, an attacker could manipulate overdue payment penalties, potentially allowing borrowers to avoid penalties or even receive unintended financial benefits. This could lead to financial losses, accounting discrepancies, and erosion of trust in the loan management system. Organizations may face regulatory and compliance risks if financial records are compromised or manipulated. Additionally, if exploited at scale, this could disrupt loan repayment processes and impact revenue streams. Since the vulnerability requires authenticated access, the risk is limited to insiders or compromised administrator accounts, but the impact remains significant within that scope. The lack of user interaction and ease of exploitation through simple HTTP request manipulation increase the threat level. No direct impact on confidentiality or availability is indicated, but the integrity and correctness of financial data are critically affected.

CWE-602Client-Side Enforcement of Server-Side Security (opens in a new tab)
Class weaknessLikelihood of exploit: MediumOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The product is composed of a server that relies on the client to implement a mechanism that is intended to protect the server.
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely.
Architecture and Design
If some degree of trust is required between the two entities, then use integrity checking and strong authentication to ensure that the inputs are coming from a trusted source.
OWASP Cheat Sheets
Docker Security (opens in a new tab)
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
Access Control (opens in a new tab)
Authorization Testing Automation (opens in a new tab)
OWASP ASVS 4.0.3
V1.4.1 (opens in a new tab)
V1.5.3 (opens in a new tab)
V4.1.1 (opens in a new tab)
Attack patterns
Manipulating Hidden Fields (opens in a new tab)
Create Malicious Client (opens in a new tab)
Removing Important Client Functionality (opens in a new tab)
Removing/short-circuiting 'Purse' logic: removing/mutating 'cash' decrements (opens in a new tab)
Accessing/Intercepting/Modifying HTTP Cookies (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

github.com/meifukun/Web-Security-PoCs/blob/main/Loan-Management-System/BusinessLogic-LoanPlan-NegativePenalty.md (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 1 Apr 2026, 14:24 UTC

WeaknessesCWE-602

Technical details

References

Community reviews

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