CVE-2025-9116 is a reflected Cross-Site Scripting (XSS) vulnerability identified in the WPS Visitor Counter WordPress plugin, affecting versions up to and including 1.4.8. The root cause is the plugin's failure to properly escape the $_SERVER['REQUEST_URI'] server variable before embedding it into an HTML attribute in the plugin's output. This improper handling allows an attacker to craft a malicious URL containing JavaScript code within the REQUEST_URI, which, when visited by a user, is reflected back and executed in the victim's browser context. The vulnerability is particularly effective against older browsers that lack modern XSS protections such as Content Security Policy (CSP) enforcement or built-in XSS filters. According to the CVSS 3.1 vector (AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:L), the attack can be launched remotely over the network without authentication but requires user interaction (clicking a malicious link). The attack complexity is high due to the need to bypass some protections, and the scope is changed because the vulnerability can affect the confidentiality, integrity, and availability of the user session or data. The impact includes potential theft of cookies, session tokens, or other sensitive information, as well as possible manipulation of the displayed content or redirection to malicious sites. No known exploits have been reported in the wild, and no official patches have been released at the time of publication. The vulnerability is categorized under CWE-79, which is a common web application security weakness related to improper neutralization of input leading to script injection.

For European organizations, the impact of CVE-2025-9116 can be significant, especially for those relying on WordPress sites with the WPS Visitor Counter plugin installed. Successful exploitation could lead to session hijacking, data theft, or defacement of websites, undermining user trust and potentially leading to regulatory compliance issues under GDPR if personal data is compromised. The reflected XSS could also be used as a vector for delivering further malware or phishing attacks targeting European users. Given the medium severity and the requirement for user interaction, the immediate risk is moderate but could escalate if combined with social engineering campaigns. Organizations operating e-commerce, government, or critical infrastructure websites are particularly at risk due to the potential reputational damage and operational disruption. Additionally, older browsers still in use within some European sectors may increase the likelihood of successful exploitation.

To mitigate CVE-2025-9116, European organizations should first verify if the WPS Visitor Counter plugin is installed and identify the version in use. Since no official patch is currently available, immediate mitigation steps include disabling or uninstalling the plugin to eliminate the attack surface. If the plugin is essential, organizations should implement input validation and output encoding measures to ensure that the REQUEST_URI parameter is properly sanitized before being rendered. Employing a Web Application Firewall (WAF) with robust XSS detection and filtering capabilities can help block malicious payloads targeting this vulnerability. Additionally, enforcing Content Security Policy (CSP) headers can reduce the impact of reflected XSS by restricting script execution sources. Organizations should also educate users about the risks of clicking suspicious links and encourage the use of modern browsers with built-in XSS protections. Monitoring web server logs for unusual REQUEST_URI patterns can aid in early detection of exploitation attempts. Finally, maintain regular backups and incident response plans to quickly recover from any successful attacks.