CVE-2025-10940 is a cross-site scripting (XSS) vulnerability identified in Total.js CMS version 1.0.0, specifically within the 'layouts_save' function of the Layout Page component located in the /admin/ directory. The vulnerability arises from insufficient sanitization or validation of the HTML argument passed to this function, allowing an attacker to inject malicious scripts. This flaw can be exploited remotely without authentication, although the CVSS vector indicates that some privileges are required (PR:H) and user interaction is necessary (UI:P). The vulnerability does not impact confidentiality or availability directly but can lead to integrity issues and session hijacking or other client-side attacks. The vendor was notified but did not respond, and no official patch or mitigation has been released. The exploit code has been made public, increasing the risk of exploitation. The CVSS score of 4.8 (medium severity) reflects the moderate impact and the complexity of exploitation due to required privileges and user interaction. This vulnerability is significant because Total.js CMS is used to manage website content, and exploitation could allow attackers to execute arbitrary JavaScript in the context of the administrator's browser, potentially leading to credential theft, privilege escalation, or further compromise of the CMS environment.

For European organizations using Total.js CMS 1.0.0, this vulnerability poses a risk primarily to the integrity of their web administration interfaces. Successful exploitation could allow attackers to execute malicious scripts within the admin panel, leading to session hijacking, unauthorized actions, or the injection of malicious content into websites managed by the CMS. This could result in reputational damage, data integrity issues, and potential regulatory non-compliance under GDPR if personal data is exposed or manipulated. The requirement for some level of privilege and user interaction reduces the likelihood of widespread automated exploitation but does not eliminate targeted attacks, especially against high-value targets such as government websites, financial institutions, or critical infrastructure operators in Europe. The lack of vendor response and absence of patches increases the urgency for organizations to implement compensating controls to mitigate risk.

Given the absence of an official patch, European organizations should implement the following specific mitigations: 1) Restrict access to the /admin/ interface using network-level controls such as IP whitelisting or VPN access to limit exposure to trusted users only. 2) Employ web application firewalls (WAFs) with custom rules to detect and block malicious payloads targeting the 'layouts_save' function or suspicious HTML input patterns. 3) Conduct thorough input validation and sanitization on the server side if customization of the CMS is possible, ensuring that HTML inputs are properly escaped or filtered. 4) Educate administrators about the risk of interacting with untrusted content or links while logged into the CMS to reduce the risk of user interaction exploitation. 5) Monitor logs and user activity for unusual behavior indicative of exploitation attempts. 6) Plan for an upgrade or migration to a patched or alternative CMS solution once available, as reliance on an unpatched vulnerable system is inherently risky.