CVE-2025-11926 is a stored Cross-Site Scripting (XSS) vulnerability identified in the Related Posts Lite plugin for WordPress, developed by wpdreams. The vulnerability arises from improper neutralization of input during web page generation (CWE-79), specifically due to insufficient input sanitization and output escaping in the plugin's admin settings interface. This flaw allows authenticated attackers with administrator-level permissions or higher to inject arbitrary JavaScript code into pages managed by the plugin. The malicious scripts are stored persistently and execute whenever any user accesses the infected page, potentially leading to session hijacking, privilege escalation, or defacement. Notably, this vulnerability only affects multi-site WordPress installations or single-site setups where the unfiltered_html capability has been disabled, limiting its scope. The CVSS v3.1 base score is 4.4, indicating medium severity, with the vector reflecting network attack vector, high attack complexity, high privileges required, no user interaction, and a scope change. No public exploits have been reported yet, but the vulnerability's presence in a widely used WordPress plugin necessitates attention. The lack of available patches at the time of publication further increases risk for affected sites. The vulnerability's exploitation requires administrative access, which means initial compromise or insider threat scenarios are prerequisites. However, once exploited, it can undermine the confidentiality and integrity of site data and user sessions.

For European organizations, the impact of CVE-2025-11926 can be significant in environments where WordPress multi-site installations are used with the Related Posts Lite plugin. Exploitation could lead to unauthorized script execution, enabling attackers to steal session cookies, perform actions on behalf of legitimate users, or inject malicious content that damages brand reputation. This could result in data breaches, loss of customer trust, and regulatory non-compliance under GDPR if personal data is compromised. The requirement for administrator-level access limits the attack surface but also means that insider threats or attackers who have already gained elevated privileges can leverage this vulnerability to escalate their control. Since many European businesses rely on WordPress for content management, especially in sectors like media, education, and e-commerce, the vulnerability poses a risk to website integrity and availability of services. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers often develop exploits for such vulnerabilities post-disclosure. Additionally, multi-site installations are common in large organizations and agencies, increasing the potential impact scope within Europe.

European organizations should immediately audit their WordPress installations to identify the presence of the Related Posts Lite plugin, particularly in multi-site environments or where unfiltered_html is disabled. Until an official patch is released, administrators should restrict plugin usage or disable it if feasible. Implement strict access controls to limit administrator privileges only to trusted personnel and monitor for unusual administrative activity. Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious script injections targeting the plugin's admin settings. Regularly review and sanitize all inputs in the WordPress admin area and consider enabling Content Security Policy (CSP) headers to mitigate the impact of injected scripts. Organizations should also keep WordPress core and all plugins updated and subscribe to vulnerability advisories for timely patching. Conduct internal security training to raise awareness about the risks of privilege misuse and ensure that multi-site configurations are hardened according to best practices. Finally, implement logging and monitoring to detect potential exploitation attempts early.