CVE-2025-3774 is a high-severity vulnerability affecting the Wise Chat plugin for WordPress, developed by marcinlawrowski. The vulnerability is a Stored Cross-Site Scripting (XSS) flaw classified under CWE-79, which arises from improper neutralization of input during web page generation. Specifically, the issue stems from insufficient sanitization and escaping of the X-Forwarded-For HTTP header in all versions of Wise Chat up to and including version 3.3.4. An unauthenticated attacker can exploit this vulnerability by injecting arbitrary malicious scripts into the X-Forwarded-For header. These scripts are then stored and rendered on pages served by the plugin, causing the payload to execute in the browsers of any users who visit the affected pages. The vulnerability does not require any authentication or user interaction to be exploited, and the attack vector is network accessible (AV:N). The CVSS v3.1 base score is 7.2, reflecting a high severity level with low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and a scope change (S:C) indicating that the vulnerability affects components beyond the initially vulnerable component. The impact affects confidentiality and integrity to a limited extent (C:L/I:L) but does not affect availability (A:N). While no known exploits are currently reported in the wild, the vulnerability's characteristics make it a significant risk, especially for websites using the Wise Chat plugin to facilitate user communication. Attackers could leverage this vulnerability to steal session cookies, perform actions on behalf of users, or deliver further malware payloads via the victim's browser, potentially compromising user accounts and site integrity.

For European organizations, the impact of this vulnerability can be substantial, particularly for those relying on WordPress sites with the Wise Chat plugin installed. The stored XSS can lead to user session hijacking, defacement, phishing, and distribution of malware, undermining user trust and potentially violating data protection regulations such as GDPR due to unauthorized access or leakage of personal data. Organizations in sectors with high user interaction on their websites—such as e-commerce, government portals, educational institutions, and media—are at increased risk. The compromise of user accounts or administrative sessions could lead to further exploitation, including unauthorized data access or site manipulation. Additionally, reputational damage and potential legal consequences from data breaches or non-compliance with privacy laws could result. The vulnerability’s ability to be exploited without authentication and user interaction increases the risk of automated mass exploitation campaigns targeting vulnerable European websites, amplifying the threat landscape.

1. Immediate patching: Although no official patch links are provided, organizations should monitor the vendor’s official channels for updates or patches addressing this vulnerability and apply them promptly once available. 2. Web Application Firewall (WAF) rules: Deploy and tune WAFs to detect and block malicious payloads in the X-Forwarded-For header, including typical XSS attack patterns and suspicious script tags. 3. Input validation and output encoding: If custom modifications or interim fixes are possible, implement strict input validation on the X-Forwarded-For header and ensure proper output encoding to neutralize scripts before rendering. 4. Disable or restrict the use of the X-Forwarded-For header if not required for legitimate purposes, or sanitize it at the proxy/load balancer level. 5. Monitor logs for unusual or suspicious X-Forwarded-For header values that may indicate exploitation attempts. 6. Educate site administrators and developers about the risks of stored XSS and the importance of secure coding practices. 7. Conduct regular security assessments and penetration tests focusing on input handling and plugin vulnerabilities. 8. Consider temporary disabling or replacing the Wise Chat plugin with alternative secure communication tools until a patch is available.