CVE-2025-11267 is a stored Cross-Site Scripting (XSS) vulnerability classified under CWE-80, found in the VK All in One Expansion Unit plugin for WordPress. The vulnerability stems from insufficient input sanitization and output escaping of the '_veu_custom_css' parameter, which accepts user-supplied Custom CSS values. Authenticated attackers with Contributor-level access or higher can exploit this flaw by injecting arbitrary JavaScript code into the CSS input field. Because the malicious script is stored persistently, it executes every time a user accesses the affected page, potentially compromising user sessions, stealing cookies, or performing unauthorized actions on behalf of users. The vulnerability has a CVSS 3.1 base score of 6.4, indicating medium severity, with an attack vector over the network, low complexity, privileges required at the contributor level, no user interaction needed, and a scope change due to affecting other components. No patches are currently available, and no known exploits have been reported in the wild. The plugin is widely used in WordPress environments, increasing the risk of exploitation. The vulnerability highlights the importance of proper input validation and output encoding in web applications, especially in plugins that allow user-generated content or customization.

For European organizations, this vulnerability poses a moderate risk primarily to websites running WordPress with the VK All in One Expansion Unit plugin installed. Exploitation could lead to session hijacking, unauthorized actions performed under the victim's credentials, defacement, or distribution of malware via injected scripts. This can damage organizational reputation, lead to data breaches involving user information, and potentially cause regulatory compliance issues under GDPR if personal data is compromised. Since the attack requires authenticated access at the Contributor level or above, organizations with lax user permission management or many contributors are at higher risk. The persistent nature of stored XSS means that even passive users visiting affected pages can be impacted. The vulnerability could also be leveraged as a foothold for further attacks within the network. Given the widespread use of WordPress in Europe, especially among SMEs and public sector websites, the impact could be significant if not addressed promptly.

1. Monitor for official patches or updates from the kurudrive vendor and apply them immediately once available. 2. Until patches are released, restrict Contributor-level and higher user permissions to trusted personnel only, minimizing the number of users who can inject content. 3. Implement Web Application Firewall (WAF) rules to detect and block malicious payloads targeting the '_veu_custom_css' parameter. 4. Conduct regular audits of user-generated CSS or content inputs to detect suspicious or unauthorized scripts. 5. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts on affected web pages. 6. Educate site administrators and contributors about the risks of injecting untrusted code and enforce strict input validation policies. 7. Consider disabling or replacing the vulnerable plugin if immediate patching is not feasible. 8. Use security plugins that can detect and sanitize stored XSS attempts in WordPress environments. 9. Regularly backup website data to enable quick restoration if an attack occurs.