CVE-2025-3748 is a Stored Cross-Site Scripting (XSS) vulnerability affecting the Taxonomy Chain Menu plugin for WordPress, developed by realmag777. This vulnerability exists in all versions up to and including 1.0.8 due to improper input sanitization and output escaping of user-supplied attributes in the plugin's pn_chain_menu shortcode. Specifically, authenticated users with contributor-level permissions or higher can inject arbitrary JavaScript code into pages via crafted shortcode attributes. Because the injected scripts are stored persistently, they execute whenever any user accesses the affected page, potentially compromising session tokens, cookies, or performing actions on behalf of the user. The vulnerability requires no user interaction beyond visiting the injected page, and the attack scope is limited to WordPress sites using this plugin. The CVSS v3.1 base score is 6.4 (medium severity), reflecting network exploitability (AV:N), low attack complexity (AC:L), privileges required (PR:L), no user interaction (UI:N), and a scope change (S:C) with low impact on confidentiality and integrity but no impact on availability. No known public exploits have been reported yet, and no patches are currently available. The vulnerability was published on May 2, 2025, and has been assigned CWE-79, indicating improper neutralization of input during web page generation leading to XSS.

For European organizations, this vulnerability poses a moderate risk primarily to websites running WordPress with the Taxonomy Chain Menu plugin installed. Exploitation could lead to session hijacking, defacement, or unauthorized actions performed under the context of legitimate users, potentially exposing sensitive information or damaging organizational reputation. Since contributor-level access is required, insider threats or compromised accounts could be leveraged to exploit this vulnerability. Sectors with high reliance on WordPress for public-facing or intranet portals—such as media, education, government, and SMEs—may be particularly affected. The scope change in the CVSS vector indicates that the vulnerability could impact components beyond the initially vulnerable plugin, potentially affecting other parts of the website or integrated systems. While no availability impact is noted, the confidentiality and integrity impacts, though low, could facilitate further attacks or data leakage. The lack of known exploits in the wild reduces immediate risk but does not eliminate it, especially given the ease of exploitation and the widespread use of WordPress in Europe.

Given the absence of an official patch, European organizations should implement the following specific mitigations: 1) Restrict contributor-level access strictly to trusted users and review user permissions regularly to minimize the risk of malicious shortcode injection. 2) Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious shortcode attribute patterns or script injection attempts targeting the pn_chain_menu shortcode. 3) Implement Content Security Policy (CSP) headers to restrict execution of unauthorized scripts on affected sites, limiting the impact of any successful injection. 4) Conduct thorough code reviews and consider temporarily disabling or replacing the Taxonomy Chain Menu plugin until a patch is released. 5) Monitor website logs for unusual shortcode usage or unexpected page modifications indicative of exploitation attempts. 6) Educate content contributors about the risks of injecting untrusted content and enforce input validation on the content management side. 7) Prepare incident response plans specific to XSS incidents, including session invalidation and user notification procedures.