CVE-2025-11835 identifies a missing authorization vulnerability (CWE-862) in the WordPress plugin 'Paid Membership Subscriptions – Effortless Memberships, Recurring Payments & Content Restriction' developed by cozmoslabs. The vulnerability exists in the PMS_AJAX_Checkout_Handler::process_payment() function, which lacks proper capability and validation checks before processing auto-renewal payments. This flaw allows unauthenticated attackers to invoke stored auto-renew charges on behalf of arbitrary members without any authentication or user interaction. The vulnerability affects all versions up to and including 2.16.4. The CVSS v3.1 score is 5.3 (medium severity), reflecting that the attack vector is network-based with low complexity and no privileges or user interaction required, but the impact is limited to integrity (unauthorized modification of payment data) without affecting confidentiality or availability. No patches have been linked yet, and no known exploits are reported in the wild. The vulnerability could lead to unauthorized financial transactions, potentially causing monetary loss to members and reputational damage to organizations using the plugin. Since the plugin is widely used for managing memberships and recurring payments on WordPress sites, the risk is significant for websites relying on this functionality. The lack of authorization checks indicates a design oversight in the plugin's payment processing logic, which should enforce strict validation of user capabilities before executing sensitive actions.

For European organizations, the impact of CVE-2025-11835 can be substantial, particularly for businesses that depend on the affected WordPress plugin to manage paid memberships and recurring payments. Unauthorized triggering of auto-renew charges can lead to financial losses for customers and disputes that damage customer trust and brand reputation. Organizations may face increased support costs and potential regulatory scrutiny under GDPR if customer payment data or transaction integrity is compromised. While the vulnerability does not expose confidential data or disrupt service availability, the integrity breach in payment processing undermines transactional trust. E-commerce platforms, subscription-based services, and content providers using this plugin are at heightened risk. The attack's unauthenticated nature increases the threat surface, allowing remote exploitation without prior access. This could also facilitate fraudulent transactions that may be difficult to trace back to the attacker, complicating incident response and remediation efforts. Additionally, the reputational damage from unauthorized charges can lead to customer churn and legal liabilities in jurisdictions with strong consumer protection laws.

1. Immediately monitor all WordPress sites using the 'Paid Membership Subscriptions' plugin for unusual or unauthorized auto-renewal payment activities. 2. Restrict access to the WordPress admin and AJAX endpoints by implementing IP whitelisting or web application firewall (WAF) rules to block suspicious requests targeting the process_payment function. 3. Apply any official patches or updates from cozmoslabs as soon as they are released to address this vulnerability. 4. In the absence of patches, consider temporarily disabling the auto-renewal feature or the plugin itself to prevent exploitation. 5. Implement additional server-side validation and capability checks via custom code or security plugins to enforce authorization on payment processing endpoints. 6. Conduct regular security audits and penetration tests focusing on membership and payment workflows. 7. Educate site administrators about the risk and encourage immediate reporting of any irregular payment activities. 8. Maintain comprehensive logging and alerting on payment-related API calls to detect and respond to exploitation attempts promptly. 9. Review and tighten WordPress user roles and permissions to minimize exposure. 10. Coordinate with payment processors to monitor for suspicious transactions linked to affected sites.