Business Logic Error in Simple Food Ordering System

Compliance Impact

The vulnerability in the Simple Food Ordering System allows attackers to manipulate product prices during checkout, leading to corrupted order records and financial data.

While the provided information does not explicitly mention compliance with standards such as GDPR or HIPAA, the corruption of financial data and business logic errors could potentially impact regulatory compliance related to financial accuracy and data integrity.

Specifically, inaccurate financial records may violate accounting standards and regulations that require accurate transaction data, which could indirectly affect compliance frameworks that mandate data integrity and auditability.

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Executive Summary

CVE-2026-13571 is a business logic vulnerability in SourceCodester Simple Food Ordering System 1.0 that allows attackers to manipulate product prices during checkout.

The flaw exists because the application trusts client-side input for the item_price parameter without validating it against the actual prices stored in the database.

An attacker can intercept and modify the item_price value in POST requests (for example, using tools like Burp Suite) to set unauthorized discounts, make free purchases, or even create negative order totals.

This manipulation affects files such as cart.php, checkout.php, and process_order.php, leading to corrupted order records and financial data.

The root cause relates to client-side enforcement of server-side security and business logic errors.

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Impact Analysis

This vulnerability can severely impact the business by allowing attackers to manipulate prices and complete purchases at unauthorized discounted rates or even for free.

Such exploitation can lead to financial losses, corrupted order and accounting data, and damage to business integrity.

It undermines the trustworthiness of the ordering system and can cause discrepancies in revenue reporting and inventory management.

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Detection Guidance

This vulnerability can be detected by monitoring and intercepting POST requests to the application, specifically those targeting the Add-to-Cart functionality where the `item_price` parameter is sent.

Using tools like Burp Suite or similar HTTP intercepting proxies, you can capture and inspect the traffic to see if the `item_price` parameter is being manipulated client-side.

A practical detection approach involves capturing a POST request to `/cart.php` or related endpoints and checking if the `item_price` value differs from the expected price stored in the database.

• Use Burp Suite or a similar proxy to intercept HTTP POST requests to `/cart.php`.
• Inspect the `item_price` parameter in the intercepted requests for unexpected or manipulated values.
• On the server, query the database to verify if order records contain prices that do not match the official product prices.
• Example command to monitor HTTP traffic (Linux): `tcpdump -i any -A -s 0 'tcp port 80 or tcp port 443' | grep item_price`

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Mitigation Strategies

Immediate mitigation steps include implementing server-side validation of the `item_price` parameter to ensure it matches the prices stored in the database.

Reject any requests where the price is negative, zero, or does not correspond to the official product price.

Recalculate order totals exclusively on the server side rather than trusting client-supplied values.

Additionally, review and patch the affected files such as `cart.php`, `checkout.php`, and `process_order.php` to enforce these validations.

Consider temporarily disabling online ordering or restricting access to the affected endpoints until a fix is deployed.

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