CVE-2025-52335 is a Cross Site Scripting (XSS) vulnerability identified in EyouCMS version 1.7.3, specifically within the index.php file. EyouCMS is a content management system used for website management. The vulnerability arises due to insufficient sanitization or improper handling of user-supplied input in the index.php script, allowing an attacker to inject malicious scripts into web pages viewed by other users. This XSS flaw can be exploited remotely without requiring authentication, but it does require user interaction, such as a victim clicking a crafted link or visiting a malicious page. The vulnerability has a CVSS 3.1 base score of 6.1, indicating a medium severity level. The vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N indicates that the attack can be performed over the network with low attack complexity, no privileges required, but user interaction is necessary. The scope is changed, meaning the vulnerability affects components beyond the initially vulnerable component. The impact affects confidentiality and integrity to a limited extent but does not affect availability. Successful exploitation could allow attackers to steal sensitive information such as session cookies, perform actions on behalf of users, or conduct phishing attacks by injecting malicious scripts. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability is categorized under CWE-79, which is the common weakness enumeration for improper neutralization of input during web page generation leading to XSS.

For European organizations using EyouCMS 1.7.3, this vulnerability poses a risk primarily to the confidentiality and integrity of user data and web sessions. Attackers exploiting this XSS flaw could hijack user sessions, steal sensitive information, or manipulate website content, potentially damaging the organization's reputation and leading to data breaches. This is particularly concerning for organizations handling personal data under GDPR, as unauthorized access or leakage could result in regulatory penalties. The medium severity indicates that while the vulnerability is exploitable remotely and without authentication, it requires user interaction, which may limit large-scale automated exploitation. However, targeted phishing campaigns leveraging this vulnerability could be effective. The lack of availability impact means service disruption is unlikely, but the integrity and confidentiality risks remain significant. Organizations relying on EyouCMS for customer-facing websites, portals, or intranets should be vigilant, as compromised sites could be used to propagate further attacks or malware.

Given the absence of an official patch, European organizations should implement immediate compensating controls. These include: 1) Applying strict input validation and output encoding on all user-supplied data in index.php and other entry points to neutralize malicious scripts. 2) Employing Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of XSS attacks. 3) Enforcing HttpOnly and Secure flags on cookies to protect session tokens from theft via script access. 4) Conducting regular security audits and penetration testing focused on XSS vulnerabilities within EyouCMS deployments. 5) Educating users about the risks of clicking suspicious links and encouraging cautious behavior to reduce successful exploitation via user interaction. 6) Monitoring web server logs and application behavior for unusual activity that may indicate exploitation attempts. 7) Considering upgrading or migrating to a CMS version or alternative platform that addresses this vulnerability once patches become available. These measures go beyond generic advice by focusing on immediate technical controls and user awareness tailored to the specific vulnerability context.