CVE-2025-11926 is a stored cross-site scripting (XSS) vulnerability identified in the Related Posts Lite plugin for WordPress, developed by wpdreams. This vulnerability affects all versions up to and including 1.12. The root cause is improper neutralization of input during web page generation, specifically insufficient sanitization and escaping of administrator-configured inputs within the plugin's settings. An attacker with authenticated administrator-level permissions or higher can inject arbitrary JavaScript code into the plugin's admin settings. Because these settings are stored and rendered on pages viewed by other users, the injected scripts execute in the context of those users' browsers when they access the affected pages. This vulnerability is limited to multi-site WordPress installations or single-site installations where the unfiltered_html capability is disabled, as these configurations restrict HTML input and thus rely on the plugin's sanitization. The vulnerability does not require user interaction beyond visiting the injected page but does require high privileges to exploit, reducing the attack surface. The CVSS v3.1 base score is 4.4, reflecting medium severity, with vector metrics indicating network attack vector, high attack complexity, high privileges required, no user interaction, and a scope change. No public exploits have been reported to date. The vulnerability could lead to partial confidentiality and integrity impacts, such as theft of cookies, session tokens, or performing unauthorized actions on behalf of users. However, availability is not affected. Since the plugin is widely used in WordPress multi-site environments, this vulnerability poses a risk to administrators and users of affected sites.

The primary impact of CVE-2025-11926 is the potential for stored cross-site scripting attacks that can compromise user confidentiality and integrity within affected WordPress multi-site installations. An attacker with administrator privileges can inject malicious scripts that execute in the browsers of other users, potentially leading to session hijacking, credential theft, or unauthorized actions performed with the victim's privileges. Although exploitation requires high privileges, insider threats or compromised administrator accounts could leverage this vulnerability to escalate attacks. The vulnerability does not affect availability directly but can undermine trust in the affected websites and lead to reputational damage. Organizations relying on the Related Posts Lite plugin in multi-site configurations or with unfiltered_html disabled are at risk, especially those with large user bases or sensitive data. The medium CVSS score reflects a moderate risk; however, the scope change indicates that the vulnerability can affect components beyond the initially compromised privilege boundary, increasing potential impact. Since no known exploits exist in the wild, the risk is currently theoretical but should be addressed proactively to prevent future exploitation.

To mitigate CVE-2025-11926, organizations should first update the Related Posts Lite plugin to a version that addresses this vulnerability once released by the vendor. In the absence of an official patch, administrators should restrict plugin access strictly to trusted users with administrator privileges and monitor for any suspicious changes in plugin settings. Implementing a Web Application Firewall (WAF) with rules to detect and block malicious script payloads in HTTP requests can help reduce risk. Additionally, enabling Content Security Policy (CSP) headers to restrict the execution of inline scripts and untrusted sources can limit the impact of injected scripts. Regularly auditing user accounts and permissions to minimize the number of administrators reduces the attack surface. For multi-site installations, consider isolating critical sites or limiting plugin usage to reduce exposure. Finally, educate administrators about the risks of injecting untrusted content and encourage the use of secure input methods. Monitoring logs for unusual activity related to plugin settings changes can provide early detection of exploitation attempts.