CVE-2025-3020 is a medium-severity cross-site scripting (XSS) vulnerability classified under CWE-79, affecting all versions of Wiesemann & Theis ERP-Gateway devices, specifically the 12x Digital Input and 6x Digital Relais models. This vulnerability arises from improper neutralization of input during web page generation, allowing a low-privileged remote attacker to inject arbitrary web scripts or HTML code into multiple fields of the device's configuration webpage. The injection occurs via crafted payloads that are not properly sanitized or encoded before being reflected in the web interface. Exploitation requires no authentication but does require user interaction, such as an administrator or operator viewing the compromised configuration page. The CVSS v3.1 base score is 5.4, reflecting a network attack vector with low attack complexity, no privileges required, user interaction needed, and limited impact on confidentiality and integrity, with no impact on availability. Although no known exploits are currently reported in the wild, the vulnerability could be leveraged to execute malicious scripts in the context of the victim's browser session, potentially leading to session hijacking, credential theft, or manipulation of device settings if combined with other weaknesses. The ERP-Gateway devices are typically used in industrial or building automation environments to interface digital inputs and relay outputs, making them critical components in operational technology (OT) networks. The vulnerability's limited impact suggests that while it does not directly compromise device availability or cause significant data leakage, it poses a risk to the integrity of the management interface and the confidentiality of session data. Given the nature of the devices and their deployment, exploitation could indirectly affect industrial processes or building management systems if attackers gain persistent access or escalate privileges through chained attacks.

For European organizations, especially those operating in industrial automation, manufacturing, building management, or critical infrastructure sectors, this vulnerability presents a moderate risk. Successful exploitation could allow attackers to execute malicious scripts in the context of administrative users managing the ERP-Gateway devices, potentially leading to unauthorized changes in device configuration or disclosure of sensitive session information. This could disrupt operational processes or provide a foothold for further lateral movement within OT networks. Although the direct impact on availability is minimal, the integrity and confidentiality risks could have cascading effects on safety and operational reliability. Organizations relying on Wiesemann & Theis ERP-Gateway devices should be aware that attackers do not need prior credentials to attempt exploitation, increasing the threat surface. The limited impact rating does not diminish the importance of addressing this vulnerability in environments where these devices control critical inputs and relay outputs, as manipulation could lead to physical process disruptions or safety hazards. Additionally, the lack of known exploits in the wild suggests a window of opportunity for proactive mitigation before active exploitation occurs.

To mitigate CVE-2025-3020, European organizations should implement the following specific measures: 1) Immediately restrict network access to the ERP-Gateway web interface by implementing network segmentation and firewall rules that limit access only to trusted administrative hosts and networks. 2) Employ strong authentication and session management controls on the device management interface to reduce the risk of session hijacking or unauthorized access. 3) Monitor and audit web interface access logs for unusual or suspicious activity indicative of attempted XSS exploitation. 4) Since no official patches are currently available, apply virtual patching techniques such as web application firewalls (WAFs) configured to detect and block common XSS payload patterns targeting the ERP-Gateway interface. 5) Educate administrators and operators about the risks of interacting with untrusted or unexpected configuration pages and encourage the use of secure browsers with script-blocking extensions during device management. 6) Engage with Wiesemann & Theis for timely updates or firmware patches addressing this vulnerability and plan for prompt deployment once available. 7) Conduct regular security assessments and penetration tests focusing on OT network devices to identify and remediate similar input validation weaknesses.