CVE-2025-9219 is a medium-severity vulnerability affecting the Post SMTP – WP SMTP Plugin with Email Logs and Mobile App for Failure Notifications, a WordPress plugin that integrates SMTP services such as Gmail SMTP, Office 365, Brevo, Mailgun, and Amazon SES. The vulnerability arises from a missing authorization check in the 'update_post_smtp_pro_option_callback' function. This flaw allows authenticated users with Subscriber-level access or higher to modify plugin settings without proper permission validation. Specifically, attackers can enable pro extensions of the plugin, which could lead to unauthorized feature activation or configuration changes. The vulnerability is classified under CWE-862 (Missing Authorization), indicating that the plugin fails to verify whether the user has the right to perform certain actions. The CVSS 3.1 base score is 4.3 (medium), with an attack vector of network (remote), low attack complexity, requiring privileges (authenticated user), no user interaction, and impacts integrity but not confidentiality or availability. No known exploits are currently reported in the wild, and the vulnerability affects all versions up to and including 3.4.1. The lack of a patch link suggests that a fix may not yet be publicly available or is pending release. This vulnerability could be exploited by low-privilege users who have access to the WordPress backend, potentially leading to unauthorized changes in email notification settings or enabling premium features without authorization, which could be leveraged for further attacks or abuse of the email infrastructure integrated with the plugin.

For European organizations using WordPress websites with the Post SMTP plugin, this vulnerability poses a risk of unauthorized configuration changes by low-privilege users such as subscribers or contributors. While the direct impact on confidentiality and availability is limited, the integrity of email notification settings can be compromised. This could lead to unauthorized activation of pro features, potentially increasing the attack surface or enabling malicious email behaviors such as spamming or phishing campaigns originating from legitimate infrastructure. Organizations relying on this plugin for critical email delivery (e.g., transactional emails, failure notifications) may experience disruptions or misuse of their email systems. Additionally, unauthorized changes could undermine trust in communications or lead to compliance issues under regulations like GDPR if email logs or notifications are manipulated. The medium severity indicates that while the vulnerability is not critical, it should be addressed promptly to prevent misuse, especially in environments where multiple users have backend access with subscriber-level privileges.

European organizations should immediately audit their WordPress installations to identify the presence of the Post SMTP plugin and verify the version in use. Until an official patch is released, administrators should restrict backend access to trusted users only, minimizing the number of accounts with subscriber-level or higher privileges. Implementing strict role-based access control (RBAC) and monitoring user activities related to plugin settings is essential. Consider temporarily disabling the plugin if it is not critical or replacing it with alternative SMTP plugins that have a strong security track record. Additionally, organizations should monitor email logs for unusual activity that might indicate exploitation attempts. Once a patch becomes available, prioritize timely updates. Employing Web Application Firewalls (WAFs) with rules to detect and block unauthorized POST requests targeting the vulnerable function could provide interim protection. Finally, educating users about the risks of unauthorized access and enforcing strong authentication mechanisms (e.g., two-factor authentication) for WordPress backend access will reduce the likelihood of exploitation.