The vulnerability identified as CVE-2025-12752 affects the Subscriptions & Memberships for PayPal plugin for WordPress, versions up to and including 1.1.7. The root cause is insufficient verification of the authenticity of Instant Payment Notification (IPN) requests from PayPal. IPN is a message service that notifies merchants about events related to PayPal transactions. The plugin fails to properly validate that these IPN messages are genuinely from PayPal, which is a classic example of CWE-345: Insufficient Verification of Data Authenticity. As a result, an unauthenticated attacker can craft and send fake IPN requests to the plugin, causing it to record fraudulent payment entries. This undermines the integrity of the payment records, potentially allowing attackers to gain unauthorized access to subscription services or memberships without paying. The vulnerability does not expose confidential data nor does it cause denial of service; it solely impacts data integrity. Exploitation is straightforward since it requires no authentication or user interaction and can be performed remotely over the network. Currently, no public exploits or active exploitation in the wild have been reported. The CVSS v3.1 base score is 5.3, reflecting a medium severity level, with attack vector network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and impact limited to integrity (I:L).

For European organizations using the affected WordPress plugin to manage PayPal subscriptions and memberships, this vulnerability poses a risk of financial fraud and business process disruption. Attackers can create fake payment records, potentially granting unauthorized access to paid services or products without actual payment. This can lead to revenue loss, inaccurate financial reporting, and erosion of customer trust. Organizations relying on automated subscription management may face challenges in reconciling payments and subscriptions, increasing operational overhead. While the vulnerability does not compromise customer data confidentiality or system availability, the integrity breach can have significant financial and reputational consequences. E-commerce businesses, digital content providers, and membership-based services in Europe that use this plugin are particularly vulnerable. The lack of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially as the vulnerability is publicly disclosed.

Immediate mitigation involves monitoring for updates from the plugin vendor and applying patches as soon as they become available. Since no patch links are currently provided, organizations should implement manual verification of IPN messages by validating the IPN payload with PayPal's servers before processing payments. This can be done by following PayPal's IPN verification protocol, which involves sending the received IPN data back to PayPal for confirmation. Additionally, organizations should audit their current payment records for suspicious or unauthorized entries and implement logging and alerting on payment processing anomalies. Restricting access to the IPN endpoint by IP whitelisting PayPal IP ranges can reduce exposure. Employing web application firewalls (WAFs) with rules to detect and block malformed or suspicious IPN requests can provide an additional layer of defense. Finally, educating developers and administrators about secure handling of third-party payment notifications is critical to prevent similar issues.