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.

Classification

CVE ID: CVE-2025-3889

CVSS Base Severity: MEDIUM

CVSS Base Score: 5.3

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

Affected Products

Vendor: mra13

Product: WordPress Simple Shopping Cart

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 10.67% (scored less or equal to compared to others)

EPSS Date: 2025-05-30 (when was this score calculated)

Stakeholder-Specific Vulnerability Categorization (SSVC)

SSVC Exploitation: none

SSVC Technical Impact: partial

SSVC Automatable: true

References

https://nvd.nist.gov/vuln/detail/CVE-2025-3889
https://www.wordfence.com/threat-intel/vulnerabilities/id/41212533-535e-4a9e-a9b8-1240021a3752?source=cve
https://plugins.trac.wordpress.org/browser/wordpress-simple-paypal-shopping-cart/tags/5.1.2/wp_shopping_cart.php#L324
https://www.tipsandtricks-hq.com/ecommerce/wp-shopping-cart
https://www.tipsandtricks-hq.com/ecommerce/simple-shopping-cart-enabling-manual-offline-checkout
https://plugins.trac.wordpress.org/changeset/3284572/

Timeline