CVE-2025-13969 is a stored Cross-Site Scripting (XSS) vulnerability identified in the Reviews Sorted plugin for WordPress, developed by eurisko. The vulnerability arises from improper neutralization of input during web page generation, specifically through the 'space' parameter in the [reviews-slider] shortcode. Versions up to and including 2.4.2 fail to adequately sanitize and escape this input, allowing authenticated users with Contributor-level permissions or higher to inject arbitrary JavaScript code. This malicious code is stored persistently and executed in the browsers of any users who visit the compromised pages, potentially leading to session hijacking, privilege escalation, or unauthorized actions within the affected WordPress site. The vulnerability has a CVSS 3.1 base score of 6.4, reflecting medium severity, with an attack vector of network (remote), low attack complexity, requiring privileges (Contributor or above), no user interaction needed, and a scope change due to impact on other components. No known public exploits have been reported yet. The flaw stems from insufficient input validation and output encoding, common issues in web application security, particularly in plugins that handle user-generated content. Since WordPress powers a significant portion of websites globally, and plugins extend its functionality, vulnerabilities in popular plugins like Reviews Sorted can have widespread impact. The vulnerability was published on December 12, 2025, and is tracked under CWE-79 (Improper Neutralization of Input During Web Page Generation).

For European organizations, this vulnerability poses a moderate risk primarily to websites using the Reviews Sorted plugin on WordPress. Exploitation can lead to unauthorized script execution in users' browsers, enabling attackers to steal session cookies, perform actions on behalf of users, or deliver further malware. This can compromise the confidentiality and integrity of user data and site content, potentially damaging organizational reputation and user trust. E-commerce platforms, news portals, and community sites that rely on user-generated content and have contributors with posting privileges are particularly vulnerable. The attack requires authenticated access but no further user interaction, making insider threats or compromised contributor accounts a significant risk vector. While availability impact is minimal, the scope change indicated by the CVSS vector suggests that the vulnerability could affect multiple components or users beyond the initial attacker. Given the widespread use of WordPress in Europe, especially in countries with large digital economies, the potential for targeted attacks or automated exploitation campaigns exists once exploit code becomes available.

Organizations should immediately audit their WordPress installations to identify if the Reviews Sorted plugin is in use and determine the version. Since no patch links are currently available, temporary mitigations include restricting Contributor-level access to trusted users only and implementing Web Application Firewall (WAF) rules to detect and block suspicious input patterns targeting the 'space' parameter in the [reviews-slider] shortcode. Site administrators can also apply manual input validation and output escaping in the plugin code if feasible, or disable the shortcode functionality until an official update is released. Monitoring website logs for unusual script injections or unexpected content changes is critical. Additionally, educating contributors about the risks of injecting untrusted content and enforcing strict content moderation policies can reduce exploitation likelihood. Once a vendor patch is released, prompt application is essential. Regular security assessments and plugin inventory management will help prevent similar vulnerabilities in the future.