WordPress Simple PayPal Shopping Cart <= 5.1.3 - Insecure Direct Object Reference via 'quantity'

Authorization Bypass Through User-Controlled Key
CVE CVE-2025-3889
CVSS Medium (5.3)
Publicly Published April 30, 2025
Last Updated May 1, 2025
Researcher Jack Taylor
Description

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.

References

1 affected software package

Software Type Plugin
Software Slug wordpress-simple-paypal-shopping-cart (view on wordpress.org)
Patched? Yes
Affected Version
  • <= 5.1.3
Patched Version
  • 5.1.4
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