CVE-2025-27851
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedThe 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe Garmin WDU web interface suffers from Cross-Site WebSocket Hijacking (CSWSH) due to missing or inadequate Origin header validation during WebSocket handshake. Since the device uses WebSockets to transmit administrative settings, an attacker who tricks a user on a multihomed host (connected to both the Garmin Marine Network and another network) to visit a malicious site can hijack the WebSocket connection and gain full administrative control of the WDU.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 1.4.6= 5.00CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the firmware version of the Garmin Empirbus Wireless Display UnitAccess the device web interface and navigate to Settings > System > About, or check the device firmware version through its administrative consoleAffected if The firmware version is 1.4.6 or 5.00 exactly
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Verify the device web interface is accessible and uses WebSocketsAccess the WDU web interface over HTTP/HTTPS and inspect page source or network traffic for WebSocket (ws:// or wss://) connections being establishedAffected if The web interface loads and establishes WebSocket connections to the device
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Confirm the device is connected to a network accessible from other networksReview network topology to determine if the Garmin Marine Network shares a switch, router, or VPN with untrusted networks, or if any host is multihomed (connected to both the marine network and another network)Affected if The device or any host on its network can be reached from an untrusted network or shares network infrastructure with other networks
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Test Origin header validation on WebSocket handshakeSend a WebSocket handshake request with an arbitrary Origin header (e.g., Origin: http://malicious-site.com) to the device and observe if the connection is accepted without proper validationAffected if The WebSocket handshake succeeds with arbitrary Origin headers, indicating missing Origin validation
A user is affected if they have a Garmin Empirbus WDU running firmware 1.4.6 or 5.00, the device web interface is accessible from their network, and the network topology allows cross-origin access (multihomed host or shared network infrastructure with untrusted networks).
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply vendor firmware update when available. In the meantime, isolate the Garmin Marine Network from untrusted networks using VLANs or air-gapping, and ensure users avoid browsing untrusted websites while connected to the marine network.
- Consultation2.0 h
- Implementation4.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-27851 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-27851 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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