The vulnerability identified as CVE-2025-15376 affects the 'Stopwords for comments' WordPress plugin developed by rndsand81. This plugin is designed to manage stopwords used in comment filtering to reduce spam or unwanted content. The issue is a Cross-Site Request Forgery (CSRF) vulnerability classified under CWE-352, caused by the absence of nonce validation in the 'set_stopwords_for_comments' and 'delete_stopwords_for_comments' functions. Nonce validation is a security mechanism in WordPress that ensures that requests to perform sensitive actions originate from legitimate users and not from forged requests. Because this validation is missing, an attacker can craft a malicious link or webpage that, when visited by a logged-in administrator, causes the plugin to add or remove stopwords without the administrator's explicit consent. This attack does not require the attacker to be authenticated but does require the administrator to interact with the malicious content (user interaction). The impact is limited to the integrity of the stopwords list, which could be manipulated to alter comment filtering behavior, potentially allowing spam or malicious comments to bypass filters or legitimate comments to be blocked. The vulnerability affects all versions up to and including 1.1 of the plugin. The CVSS v3.1 base score is 4.3, indicating a medium severity level, with an attack vector of network, low attack complexity, no privileges required, user interaction required, and impact limited to integrity. There are no known exploits in the wild at the time of publication, and no official patches have been linked yet. However, the vulnerability is publicly disclosed and should be addressed promptly.

For European organizations, especially those using WordPress websites with the 'Stopwords for comments' plugin installed, this vulnerability could lead to unauthorized modification of comment filtering rules. This can degrade the quality of user-generated content by allowing spam or malicious comments to appear or by blocking legitimate comments, potentially harming user trust and engagement. While the vulnerability does not directly compromise sensitive data confidentiality or system availability, it undermines the integrity of content moderation processes. Organizations relying on community feedback, customer reviews, or interactive comment sections may experience reputational damage or increased administrative overhead to manually manage comments. Additionally, attackers could leverage this to facilitate social engineering or phishing campaigns by manipulating comment content. The requirement for administrator interaction limits the ease of exploitation but does not eliminate the risk, especially in environments where administrators may be targeted with phishing or social engineering attacks. Given the widespread use of WordPress across Europe, the impact could be significant for small and medium enterprises, media outlets, and public sector websites that use this plugin.

To mitigate this vulnerability, organizations should first verify if the 'Stopwords for comments' plugin is installed and identify the version in use. Immediate steps include: 1) Temporarily disabling the plugin until a security patch is released. 2) Restricting administrator access to trusted networks and enforcing multi-factor authentication to reduce the risk of successful social engineering. 3) Educating administrators about the risks of clicking on unsolicited links or visiting untrusted websites while logged into the WordPress admin panel. 4) Monitoring web server logs and WordPress audit logs for unusual activity related to stopwords modification. 5) If possible, implementing Web Application Firewall (WAF) rules to detect and block suspicious POST requests targeting the vulnerable plugin endpoints. 6) Following the plugin vendor’s updates closely and applying security patches immediately once available. 7) Considering alternative plugins with better security practices for comment filtering if the vendor does not provide timely fixes. These measures go beyond generic advice by focusing on administrative behavior, access controls, and proactive monitoring specific to this vulnerability.