Cross-Site Scripting in Kieback & Peter DDC Building Controllers

Executive Summary

CVE-2026-4293 is a cross-site scripting (XSS) vulnerability affecting multiple Kieback & Peter DDC Building Controllers. This vulnerability allows an attacker to execute JavaScript code in the victim's browser, which can enable the attacker to take control of the browser.

• It affects various models including DDC4002, DDC4100, DDC4200, DDC4200-L, DDC4400, DDC520, DDC4002e, DDC4200e, DDC4400e, DDC4020e, and DDC4040e.
• The vulnerability has a CVSS v3.1 base score of 5.3, indicating medium severity.
• It is associated with CWE-79, which is the common weakness enumeration for cross-site scripting.

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Impact Analysis

If exploited, this vulnerability can allow an attacker to execute malicious JavaScript in the victim's browser, effectively giving the attacker control over the browser.

This could lead to unauthorized actions performed on behalf of the user, theft of sensitive information, or manipulation of the user interface.

Since the affected devices are used in critical infrastructure sectors such as commercial facilities, communications, financial services, food and agriculture, government services, healthcare, and information technology, exploitation could have broader operational impacts.

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Mitigation Strategies

To mitigate the CVE-2026-4293 vulnerability in Kieback & Peter DDC building controllers, several defensive measures are recommended.

• Minimize network exposure of the affected devices.
• Isolate control system networks behind firewalls.
• Use secure remote access methods such as VPNs.
• Operate end-of-maintenance devices in strictly separate OT environments.
• Restrict network access to the affected devices.
• Disable unnecessary web portal access.
• Update firmware to the latest versions where applicable.

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Compliance Impact

The vulnerability in Kieback & Peter DDC building controllers allows cross-site scripting (XSS), enabling attackers to execute JavaScript in a victim's browser and potentially control it. While the affected devices are used in critical infrastructure sectors including healthcare and government services, the provided information does not explicitly describe how this vulnerability impacts compliance with common standards and regulations such as GDPR or HIPAA.

However, given that the vulnerability could lead to unauthorized control of user browsers, it may pose risks related to data integrity and security, which are important considerations under regulations like GDPR and HIPAA. Organizations using these devices should consider the potential implications for protecting personal and sensitive data and follow recommended mitigation steps to reduce exposure.

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Detection Guidance

The CVE-2026-4293 vulnerability affects multiple Kieback & Peter DDC Building Controllers and involves cross-site scripting (CWE-79). Detection typically involves identifying the presence of affected devices and checking for vulnerable web portal access.

While no specific detection commands are provided in the available resources, general approaches include scanning your network for the affected device models (such as DDC4002, DDC4100, DDC4200, and others) and inspecting web interfaces for input fields vulnerable to cross-site scripting.

Network scanning tools like nmap can be used to identify devices by their IP addresses and open ports. For example, a command like `nmap -p 80,443 <target-ip>` can help identify web services running on these devices.

Additionally, manual or automated testing of web portals for XSS vulnerabilities can be performed using security tools such as OWASP ZAP or Burp Suite to detect if JavaScript injection is possible.

CISA recommends minimizing network exposure and isolating control system networks behind firewalls, which can also help in detecting unauthorized access attempts or suspicious traffic related to exploitation attempts.

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