CVE-2025-13746 is a stored Cross-Site Scripting (XSS) vulnerability identified in the ForumWP – Forum & Discussion Board plugin for WordPress, affecting all versions up to and including 2.1.6. The root cause is insufficient input sanitization and output escaping of the User's Display Name field, which allows authenticated users with Subscriber-level privileges or higher to inject arbitrary JavaScript code into forum pages. This malicious code is stored persistently and executed in the browsers of any users who visit the compromised pages, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of the victim. The vulnerability is exploitable remotely over the network without requiring user interaction beyond page access. The CVSS 3.1 base score is 6.4, indicating a medium severity level, with the vector showing network attack vector, low attack complexity, low privileges required, no user interaction, and a scope change. No public exploits have been reported yet, but the vulnerability's nature makes it a significant risk for WordPress sites running this plugin, especially those with active user communities. The lack of output escaping and input validation in a commonly editable field (display name) makes this vulnerability particularly dangerous as it can be exploited by relatively low-privileged users to affect other users. The vulnerability was reserved in late 2025 and published in early 2026, with no patch links currently available, indicating that users should monitor for updates or apply temporary mitigations.

For European organizations, this vulnerability poses a significant risk to the confidentiality and integrity of user sessions and data on WordPress-based community forums using the ForumWP plugin. Attackers can leverage the stored XSS to steal session cookies, perform actions on behalf of users, or deliver further payloads such as malware or phishing content. This can lead to reputational damage, data breaches, and potential regulatory non-compliance under GDPR if personal data is compromised. The impact is heightened in sectors relying heavily on community engagement or customer interaction via forums, such as e-commerce, education, and public services. The vulnerability's exploitation requires only low-level authenticated access, which may be easier to obtain through credential stuffing or social engineering. Given the widespread use of WordPress in Europe and the popularity of community forums, the scope of affected systems is broad. The lack of user interaction requirement means that once a malicious display name is set, any user visiting the forum page is at risk, increasing the potential attack surface. Although availability is not impacted, the compromise of confidentiality and integrity can have cascading effects on organizational security posture and trust.

European organizations should implement the following specific mitigations: 1) Monitor the vendor's official channels for patches and apply updates to ForumWP plugin promptly once available. 2) In the interim, restrict or sanitize user input for display names using custom filters or plugins that enforce strict character whitelisting and remove script tags or event handlers. 3) Deploy Web Application Firewalls (WAFs) with robust XSS detection and blocking capabilities tailored to WordPress environments to intercept malicious payloads before they reach the application. 4) Conduct regular security audits and code reviews of customizations around user input handling in the forum. 5) Educate forum administrators and moderators to identify and remove suspicious user profiles or content promptly. 6) Implement Content Security Policy (CSP) headers to reduce the impact of injected scripts by restricting script sources. 7) Limit the privileges of users who can change display names or require additional verification for such changes. 8) Enable logging and monitoring for unusual user behavior or script injection attempts to facilitate early detection. These measures go beyond generic advice by focusing on both immediate risk reduction and long-term security hygiene tailored to the specific plugin and threat vector.