CVE-2025-67563 identifies a missing authorization vulnerability in the Post SMTP plugin for WordPress, developed by Saad Iqbal, affecting all versions up to 3.6.1. The vulnerability arises from incorrectly configured access control security levels, which fail to properly enforce authorization checks on certain plugin functionalities. This flaw could allow an attacker, potentially without authentication, to perform unauthorized actions such as sending emails or modifying SMTP settings through the plugin interface. Post SMTP is widely used to configure and send emails via SMTP servers in WordPress environments, making it a critical component for email delivery. The lack of authorization checks means that an attacker exploiting this vulnerability could abuse the plugin to send spam, phishing emails, or malicious content, potentially damaging organizational reputation and enabling further attacks. Although no known exploits have been reported in the wild yet, the vulnerability's presence in a widely deployed plugin increases the risk of exploitation once details become public. The absence of a CVSS score limits precise severity quantification, but the nature of the flaw suggests a high impact on confidentiality and integrity, with moderate impact on availability. The vulnerability does not require user interaction, and the scope includes all installations running vulnerable versions of Post SMTP. The issue was published on December 9, 2025, with no patches currently linked, indicating the need for urgent vendor response and user vigilance.

For European organizations, this vulnerability poses significant risks to email security and operational integrity. Unauthorized use of the Post SMTP plugin could allow attackers to send fraudulent emails from legitimate domains, facilitating phishing campaigns, business email compromise (BEC), and spam distribution. This can lead to reputational damage, loss of customer trust, and potential regulatory penalties under GDPR if personal data is compromised or misused. Additionally, attackers might manipulate SMTP settings to intercept or redirect emails, impacting confidentiality and integrity of communications. Organizations relying heavily on WordPress for their web presence and communications infrastructure are particularly vulnerable. The impact extends to sectors with high email dependency such as finance, healthcare, government, and e-commerce. The absence of known exploits currently provides a window for proactive mitigation, but the risk of rapid exploitation post-disclosure remains high. Disruption of email services could also affect business continuity, especially in organizations with automated workflows dependent on email notifications.

Organizations should immediately audit their WordPress environments to identify installations of the Post SMTP plugin and verify the version in use. Until an official patch is released, administrators should restrict access to the plugin’s management interfaces to trusted users only, employing the principle of least privilege. Implementing web application firewalls (WAF) with rules to detect and block suspicious requests targeting the plugin can reduce exploitation risk. Monitoring logs for unusual email sending patterns or configuration changes is critical for early detection. Organizations should also consider temporarily disabling the plugin if email functionality can be maintained through alternative means. Once a patch is available, prompt application is essential. Additionally, enforcing multi-factor authentication (MFA) for WordPress admin accounts and regularly reviewing user roles can limit unauthorized access. Security awareness training for administrators about this vulnerability and potential phishing risks will further strengthen defenses.