CVE-2025-3874 Overview
CVE-2025-3874 affects the WordPress Simple Shopping Cart plugin (also known as WordPress Simple PayPal Shopping Cart) developed by tipsandtricks-hq. The vulnerability is an Insecure Direct Object Reference (IDOR) [CWE-639] present in all versions up to and including 5.1.3. The root cause is the lack of randomization in a user-controlled key used to identify shopping cart sessions. Unauthenticated attackers can predict or enumerate the key to access other customers' shopping carts. Once inside, attackers can edit product links, add or delete products, and enumerate coupon codes stored in the cart.
Critical Impact
Unauthenticated remote attackers can access arbitrary customer shopping carts, tamper with cart contents, and disclose coupon codes without any user interaction.
Affected Products
- tipsandtricks-hq WordPress Simple PayPal Shopping Cart plugin, all versions up to and including 5.1.3
- WordPress sites using the Simple Shopping Cart plugin for product checkout flows
- E-commerce deployments relying on the plugin's cart session logic for coupon validation
Discovery Timeline
- 2025-05-01 - CVE-2025-3874 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-3874
Vulnerability Analysis
The plugin identifies shopping cart instances using a key that is derived from user-controllable input rather than a cryptographically random value. Because the key is predictable, an attacker can guess or enumerate valid cart identifiers belonging to other users. Once the attacker binds to another user's cart context, the plugin trusts the reference and grants read and write access to the cart contents. This is a classic IDOR pattern where authorization is missing at the object level. The impact covers confidentiality (viewing carts and coupon codes) and integrity (modifying product entries and links), but not availability. Attack complexity is low and no authentication or user interaction is required.
Root Cause
The cart class does not use a secure random value such as one produced by wp_generate_password() when creating cart identifiers. Referenced source lines in includes/class-wpsc-cart.php and wp_shopping_cart.php show that the key initialization relies on values the client can influence or predict. There is no server-side authorization check binding the cart object to an authenticated session or a signed token.
Attack Vector
An unauthenticated attacker sends HTTP requests to the target WordPress site referencing a predicted cart key. The plugin resolves the key to another user's cart without validating ownership. The attacker can then issue additional requests to modify product entries, replace product URLs with attacker-controlled destinations, delete items, or read coupon codes returned by the plugin. Because the flaw is network-reachable and requires no privileges, mass enumeration against public storefronts is feasible.
No public proof-of-concept exploit code has been released. See the Wordfence Vulnerability Analysis and the WPSC Cart Class Code for technical details on the vulnerable key generation.
Detection Methods for CVE-2025-3874
Indicators of Compromise
- Unexpected modifications to product links, prices, or item counts inside customer cart records stored by the plugin.
- Access log entries showing sequential or high-volume requests to shopping cart endpoints from a single source IP.
- Coupon codes appearing in referrer chains or being redeemed from IP addresses that never visited product pages.
- WordPress database entries referencing cart keys with low entropy or predictable patterns.
Detection Strategies
- Review web server access logs for enumeration patterns against plugin endpoints such as wp_shopping_cart.php handlers.
- Compare current plugin version against 5.1.3 using WordPress admin or WP-CLI (wp plugin list) to identify vulnerable installations.
- Correlate cart modification events with the authenticated session or client fingerprint that originally created the cart.
Monitoring Recommendations
- Enable verbose logging on the WordPress site and forward logs to a centralized SIEM for pattern analysis.
- Alert on repeated 200 responses to cart endpoints from IPs that did not first request product listing pages.
- Monitor for outbound redirects from product links pointing to unknown external domains, which may indicate tampered cart entries.
How to Mitigate CVE-2025-3874
Immediate Actions Required
- Update the WordPress Simple Shopping Cart plugin to a version later than 5.1.3 that includes the fix from WordPress Changeset 3284572.
- Audit existing cart records and invalidate any active cart sessions created under the vulnerable version.
- Rotate all active coupon codes that may have been exposed through predictable cart keys.
Patch Information
The vendor addressed the issue in the changeset published at WordPress Changeset 3284572. The fix replaces the predictable key with a randomized identifier consistent with the guidance in the WordPress Function Reference for wp_generate_password(). Site administrators should apply the update through the WordPress plugin manager or via WP-CLI.
Workarounds
- If patching is not immediately possible, disable the WordPress Simple Shopping Cart plugin until the update is applied.
- Place a web application firewall rule in front of cart endpoints to rate-limit and block enumeration of cart key parameters.
- Restrict access to checkout pages behind authentication where the business model allows, reducing exposure to unauthenticated enumeration.
# Update the plugin using WP-CLI
wp plugin update wordpress-simple-paypal-shopping-cart
wp plugin list --name=wordpress-simple-paypal-shopping-cart --fields=name,version,status
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
