CVE-2025-67563 is a vulnerability identified in the Post SMTP plugin developed by Saad Iqbal, affecting versions up to and including 3.6.1. The core issue is a missing authorization mechanism that allows unauthenticated remote attackers to exploit improperly configured access control security levels within the plugin. Post SMTP is a WordPress plugin used to manage email delivery via SMTP servers, often critical for transactional and notification emails. The vulnerability's CVSS 3.1 score is 5.3, reflecting a medium severity level. The vector indicates that the attack can be performed remotely over the network (AV:N), requires low attack complexity (AC:L), no privileges (PR:N), and no user interaction (UI:N). The impact is limited to confidentiality (C:L), with no effect on integrity or availability. This suggests that an attacker could potentially access sensitive information handled by the plugin or its configuration but cannot alter data or disrupt service. No known exploits have been reported in the wild, and no patches have been linked yet, indicating that the vulnerability is newly disclosed. The lack of authorization checks means that any external actor can potentially access restricted functionality or data, depending on the plugin’s configuration and deployment context. Given that Post SMTP is widely used in WordPress environments, this vulnerability could expose email credentials or configuration details, which could be leveraged for further attacks such as phishing or email spoofing.

For European organizations, the vulnerability poses a moderate risk primarily to the confidentiality of email-related data managed by the Post SMTP plugin. Exposure of SMTP credentials or email configuration could lead to unauthorized access to email services, enabling attackers to intercept sensitive communications or send fraudulent emails. This can undermine trust, lead to data leakage, and facilitate phishing campaigns targeting employees or customers. While the vulnerability does not directly affect integrity or availability, the indirect consequences of compromised email systems can be significant, including reputational damage and regulatory non-compliance under GDPR if personal data is exposed. Organizations relying heavily on WordPress for their web presence and communications, especially those using Post SMTP for critical email functions, are at risk. The lack of required privileges or user interaction for exploitation increases the threat surface, making automated scanning and exploitation feasible. However, the absence of known exploits in the wild currently reduces immediate risk, though proactive mitigation is advised.

1. Monitor official channels for the release of a security patch for Post SMTP and apply updates immediately upon availability. 2. Until a patch is released, restrict access to the WordPress admin interface and plugin endpoints using web application firewalls (WAF) or IP whitelisting to limit exposure. 3. Review and tighten SMTP credentials and email configuration settings, ensuring minimal privilege principles are applied. 4. Implement network segmentation to isolate email servers and related services from public-facing systems. 5. Conduct regular security audits and vulnerability scans on WordPress installations to detect unauthorized access attempts. 6. Educate administrators on the risks of misconfigured plugins and enforce strong authentication mechanisms for WordPress admin accounts. 7. Consider temporary disabling or replacing Post SMTP with alternative secure email plugins if immediate patching is not possible. 8. Monitor logs for unusual email activity or access patterns that could indicate exploitation attempts.