CVE-2025-6025: WooCommerce Order Tip Auth Bypass Flaw

CVE-2025-6025 Overview

The Order Tip for WooCommerce plugin for WordPress contains an Improper Input Validation vulnerability affecting all versions up to and including 1.5.4. The flaw stems from a lack of server-side validation on the data-tip attribute, which allows unauthenticated attackers to manipulate tip amounts submitted during the checkout process. Attackers can apply excessive or negative tip values, potentially resulting in unauthorized discounts that could reduce order totals to zero.

Critical Impact

Unauthenticated attackers can exploit this vulnerability to obtain products or services at significantly reduced prices or completely free by submitting manipulated negative tip values during checkout.

Affected Products

• Order Tip for WooCommerce plugin versions up to and including 1.5.4
• WordPress installations running vulnerable versions of the plugin
• WooCommerce-based e-commerce sites utilizing the Order Tip functionality

Discovery Timeline

• 2025-08-15 - CVE-2025-6025 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-6025

Vulnerability Analysis

This vulnerability is classified under CWE-602 (Client-Side Enforcement of Server-Side Security), indicating that security controls are improperly implemented on the client side rather than being enforced server-side. The Order Tip for WooCommerce plugin relies on client-side JavaScript to handle tip amount validation, which can be trivially bypassed by an attacker.

The vulnerable code path involves the data-tip attribute within the tip form implementation. When a customer selects a tip amount during checkout, the value is passed to the server without proper sanitization or boundary checking. This architectural flaw allows attackers to intercept and modify the tip value before submission, introducing negative numbers or arbitrary values that the server processes without question.

The impact is significant for e-commerce operators: attackers can effectively create unauthorized discounts on any order by submitting negative tip amounts. Depending on the order total and the negative value submitted, this could result in drastically reduced prices or even free orders.

Root Cause

The root cause is the absence of server-side validation for the data-tip attribute in the plugin's PHP backend. The tip form implementation accepts user-supplied tip values without verifying that the amount is within acceptable bounds (positive values only) or checking for manipulation. Client-side validation in the JavaScript bundle provides no real security as it can be easily bypassed using browser developer tools or intercepting proxy tools.

Attack Vector

The attack can be executed over the network by any unauthenticated user. An attacker can exploit this vulnerability through the following approach:

1. Navigate to a WooCommerce checkout page with the Order Tip feature enabled
2. Add items to the shopping cart and proceed to checkout
3. Use browser developer tools or a proxy tool to intercept the tip submission request
4. Modify the data-tip attribute value to a negative number (e.g., -100)
5. Submit the modified request to the server
6. The server processes the negative tip, reducing the order total

The vulnerability requires no authentication, no user interaction beyond normal checkout flow, and can be exploited remotely. This makes it particularly dangerous for e-commerce sites that may process orders automatically without manual review.

Detection Methods for CVE-2025-6025

Indicators of Compromise

• Orders completed with negative tip amounts or unusually large negative adjustments
• Order totals that don't match expected calculations based on product prices
• Multiple orders from the same user or IP address with zero or near-zero totals
• Unusual patterns in tip values that fall outside the configured tip options
• Checkout sessions where the final order amount is significantly lower than cart value

Detection Strategies

• Implement logging for all tip value submissions and flag negative or out-of-range values
• Configure WooCommerce order review alerts for orders with suspicious discount patterns
• Deploy web application firewall (WAF) rules to detect and block requests with negative numeric values in tip-related parameters
• Set up database queries to identify historical orders that may have been compromised with negative tips
• Monitor HTTP request logs for modified data-tip attribute values using regex patterns

Monitoring Recommendations

• Enable detailed logging for the Order Tip plugin and WooCommerce checkout processes
• Set up automated alerts for orders completed with tips outside the expected positive range
• Implement real-time monitoring of checkout flow to detect parameter tampering attempts
• Review order reports regularly for anomalous pricing patterns that could indicate exploitation

How to Mitigate CVE-2025-6025

Immediate Actions Required

• Update the Order Tip for WooCommerce plugin to the latest patched version immediately
• Review recent orders for signs of exploitation, particularly orders with negative tip amounts or unexpectedly low totals
• Temporarily disable the Order Tip functionality if an immediate update is not possible
• Implement server-side validation as an additional security layer if modifying plugin code is feasible
• Enable manual review for all orders until the vulnerability is patched

Patch Information

The plugin developers have released a security update addressing this vulnerability. The plugin changelog documents the fix. WordPress administrators should update to the latest version via the WordPress plugin update mechanism. Additional details are available in the Wordfence Vulnerability Report.

Workarounds

• Deactivate the Order Tip for WooCommerce plugin entirely until a patched version is available
• Implement a custom server-side validation function that rejects negative tip values before order processing
• Configure WooCommerce to require manual order review and approval for all transactions
• Use a web application firewall to block requests containing negative values in tip-related form fields
• Add custom PHP code to validate tip amounts at the server level before applying to order totals

# Example: Check current plugin version in WordPress
wp plugin list --name=order-tip-woo --fields=name,version,update_version

# Update to latest version via WP-CLI
wp plugin update order-tip-woo

# Alternatively, temporarily deactivate the plugin
wp plugin deactivate order-tip-woo