What the vulnerability does
01Description
The WordPress Simple Shopping Cart plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 5.1.3 via the 'process_payment_data' due to missing validation on a user controlled key. This makes it possible for unauthenticated attackers to change the quantity of a product to a negative number, which subtracts the product cost from the total order cost. The attack will only work with Manual Checkout mode, as PayPal and Stripe will not process payments for a negative quantity.
Explanation of Vulnerability in Simple Terms
02Summary
Simple Shopping Cart versions 5.1.3 and earlier contain an integrity vulnerability that allows unauthenticated attackers to modify data over the network without user interaction. The vulnerability has a CVSS score of 5.3 (medium severity). No confidentiality or availability impact is present. Update to a version newer than 5.1.3 to remediate.
What an attacker can do
03Attacker Capabilities
Modify data in the shopping cart application without authentication.
Potential impact on your site
04Site Impact
Attackers can alter cart contents, orders, or product information without logging in.
Conditions required to exploit
05Prerequisites
Network access to the affected application; no authentication or user interaction required.
Key dates
06Disclosure timeline
May 1, 2025
CVE published
April 8, 2026
Record updated
