CVE-2025-7820 is a vulnerability classified under CWE-602, which refers to client-side enforcement of server-side security controls. The SKT PayPal for WooCommerce plugin for WordPress, widely used to integrate PayPal payment processing into WooCommerce stores, suffers from a critical design flaw where payment validation is performed solely on the client side. This means that the plugin relies on the user's browser or client environment to confirm that a payment has been made, rather than verifying this information on the server side where it cannot be tampered with. As a result, an unauthenticated attacker can manipulate client-side data or requests to bypass payment requirements entirely, effectively making confirmed purchases without paying. This vulnerability affects all versions up to and including 1.4 of the plugin. The CVSS 3.1 base score is 7.5, indicating high severity, with attack vector network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), no confidentiality impact (C:N), high integrity impact (I:H), and no availability impact (A:N). The vulnerability was reserved in July 2025 and published in November 2025, with no known exploits in the wild yet. The lack of server-side validation is a fundamental security oversight that undermines the trustworthiness of the payment process and can lead to significant financial fraud and loss for merchants using this plugin.

For European organizations operating e-commerce websites using the SKT PayPal for WooCommerce plugin, this vulnerability poses a direct financial risk due to fraudulent transactions being confirmed without payment. This can lead to revenue loss, inventory depletion, and potential chargebacks. Additionally, the integrity of the payment system is compromised, which can damage customer trust and the organization's reputation. Since the vulnerability requires no authentication or user interaction, attackers can automate exploitation at scale, increasing the risk of widespread fraud. The impact is particularly severe for small and medium-sized enterprises (SMEs) that rely heavily on WooCommerce for online sales and may lack robust fraud detection mechanisms. Regulatory compliance risks also arise, as payment fraud incidents could trigger investigations under GDPR and other financial regulations, especially if customer data is involved or if the fraud affects transaction records. The absence of availability impact means the website remains operational, potentially allowing continuous exploitation until mitigated.

Immediate mitigation steps include disabling or uninstalling the SKT PayPal for WooCommerce plugin until a secure update is released. Organizations should monitor transaction logs for anomalies such as confirmed orders without corresponding payment records. Implementing additional server-side payment verification mechanisms, such as validating payment status directly with PayPal's API before confirming orders, is critical. Merchants should also consider deploying Web Application Firewalls (WAFs) with custom rules to detect and block suspicious payment bypass attempts. Regularly updating WordPress plugins and themes to the latest versions is essential once patches are available. Conducting security audits of e-commerce workflows to ensure no client-side-only enforcement exists is recommended. Educating staff and customers about potential fraud indicators can help in early detection. Finally, organizations should prepare incident response plans to address potential fraud cases swiftly.