CVE-2024-5420 is a stored Cross-Site Scripting (XSS) vulnerability classified under CWE-79, impacting SEH Computertechnik's utnserver Pro, utnserver ProMAX, and INU-100 web interfaces up to version 20.1.22. The root cause is missing input validation during web page generation, which allows attackers to inject malicious JavaScript payloads that are stored on the server and executed in the browsers of users who access the affected interface. This vulnerability does not require any authentication or privileges to exploit, but it does require user interaction, such as an authenticated user visiting a maliciously crafted page or interface. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:L/VA:H/SC:N/SI:N/SA:H) indicates network attack vector, low attack complexity, no privileges required, user interaction needed, and high impact on confidentiality and availability, with low impact on integrity. The vulnerability can lead to session hijacking, credential theft, unauthorized actions, or malware deployment within the trusted network environment. Although no known exploits are currently reported in the wild, the high CVSS score suggests a significant risk if exploited. The affected products are commonly used in industrial and network management contexts, making them attractive targets for attackers aiming to disrupt operations or gain persistent access. The lack of available patches at the time of publication necessitates immediate interim mitigations.

For European organizations, especially those in industrial automation, manufacturing, and network infrastructure sectors using SEH Computertechnik products, this vulnerability poses a serious threat. Successful exploitation could lead to unauthorized access to sensitive operational data, session hijacking, and potential lateral movement within internal networks. This could disrupt critical industrial processes, compromise data integrity, and lead to downtime or safety incidents. Confidentiality breaches could expose proprietary or personal data, violating GDPR requirements. The requirement for user interaction limits mass exploitation but targeted spear-phishing or social engineering attacks could be effective. The high impact on confidentiality and availability makes this a critical concern for organizations relying on these systems for operational continuity and security.

1. Monitor SEH Computertechnik communications closely for official patches and apply them immediately upon release. 2. Implement strict input validation and output encoding on all web interfaces to prevent injection of malicious scripts. 3. Restrict access to the utnserver Pro and related web interfaces using network segmentation, VPNs, and strong authentication mechanisms to limit exposure. 4. Employ Web Application Firewalls (WAFs) with custom rules to detect and block XSS payloads targeting these interfaces. 5. Conduct user awareness training to reduce the risk of social engineering attacks that could trigger exploitation. 6. Regularly audit and monitor logs for unusual activities indicative of exploitation attempts. 7. Consider disabling or limiting web interface functionalities that are not essential to reduce the attack surface. 8. Use Content Security Policy (CSP) headers to mitigate the impact of potential XSS attacks by restricting script execution sources.