CVE-2025-67443 identifies a Cross Site Scripting (XSS) vulnerability in Schlix CMS versions before 2.2.9-5. The root cause is the lack of proper JavaScript sanitization in the login form, specifically in how incorrect login attempts are logged and subsequently rendered within the admin panel. When an attacker submits a specially crafted login attempt containing malicious JavaScript payloads, these payloads are stored in the logs and executed in the context of an administrator viewing the logs. This stored XSS can lead to a range of attacks including session hijacking, theft of admin credentials, unauthorized actions within the CMS, or pivoting to other parts of the network. The vulnerability does not require prior authentication to inject the payload but does require an administrator to view the logs for the payload to execute, limiting the attack vector to administrative users. No CVSS score has been assigned yet, and no public exploits have been reported. The vulnerability highlights a common security oversight in input validation and output encoding in web applications, particularly in CMS platforms that handle user input in administrative interfaces. Schlix CMS is a PHP-based content management system used primarily for website management, and its admin panel is a critical component for site control. Failure to sanitize login form inputs before logging them creates a persistent XSS vector that can be exploited remotely. The vulnerability was reserved and published in December 2025, indicating recent discovery and disclosure. Organizations using affected versions should prioritize patching and review their logging and input handling practices to prevent similar issues.

For European organizations, the impact of this vulnerability can be significant, especially for those relying on Schlix CMS to manage their websites or intranet portals. Successful exploitation could allow attackers to execute arbitrary JavaScript in the admin context, leading to administrative session hijacking, unauthorized content modification, or deployment of further malware. This could result in data breaches, defacement of websites, loss of customer trust, and potential regulatory penalties under GDPR if personal data is compromised. The attack vector requires no initial authentication to inject the payload, increasing the risk of exploitation from external threat actors. However, the payload only executes when an administrator views the logs, which somewhat limits the scope but still poses a critical risk to administrative control. Given the widespread use of CMS platforms in European public and private sectors, including government, education, and commerce, the vulnerability could disrupt critical services and damage organizational reputations. Additionally, the vulnerability could be leveraged as a foothold for more extensive network intrusions or lateral movement within corporate environments.

The primary mitigation is to upgrade Schlix CMS to version 2.2.9-5 or later, where the vulnerability has been addressed. Organizations should verify their CMS version and apply patches promptly. In addition, administrators should implement strict input validation and output encoding on all user-supplied data, especially in login forms and logging mechanisms, to prevent injection of malicious scripts. Review and sanitize existing logs to remove any potentially malicious entries. Restrict access to the admin panel and logs to trusted personnel only, and consider implementing multi-factor authentication (MFA) for administrative accounts to reduce the risk of session hijacking. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in the admin interface. Regularly audit and monitor logs for suspicious login attempts or unusual activity. Finally, conduct security awareness training for administrators to recognize and respond to potential XSS attacks.