CVE-2025-3889

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

MEDIUM
5.3
CVSS Score
Published: May 1, 2025 at 11:11 AM UTC
Updated: June 17, 2026 at 09:20 AM UTC
2 products affected across 2 vendorsWordPress Simple Paypal Shopping CartHq WordPress Simple Paypal Shopping Cart

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 5.1.4
Affected range stops below 5.1.4, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMWordfence
Vector?

Quick Info

StatusANALYZED
CWE
CWE-639

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