CWE-912Weakness · CWE-912

CVE-2026-30704

CRITICAL · 9.1 CVSS v3.1 Published 2026-03-18
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 · unedited
The WiFi Extender WDR201A (HW V2.1, FW LFMZX28040922V1.02) exposes an unprotected UART interface through accessible hardware pads on the PCB

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 confidence

The WiFi Extender WDR201A (HW V2.1, FW LFMZX28040922V1.02) exposes an unprotected UART interface through accessible hardware pads on the PCB. This physical vulnerability allows attackers with physical access to connect to the device's serial console, potentially gaining shell access or extracting sensitive data/debug information.

MitigationPhysical security controls (enclosure locking, tamper-evident seals) should be implemented; additionally, UART console access should be disabled or password-protected in firmware if possible.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS 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
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

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

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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify device model and firmware version
    Locate the device label or access the admin interface to confirm the model is WDR201A and firmware version is LFMZX28040922V1.02
    Affected if The device is a WiFi Extender WDR201A with firmware LFMZX28040922V1.02 or earlier HW V2.1 version
  2. Physically inspect PCB for exposed UART pads
    Open the device enclosure and visually examine the PCB for exposed metallic pads or pins labeled TX, RX, GND, or similar UART interfaces, typically located near the edge of the circuit board
    Affected if Unprotected UART pads are visible and accessible without tools on the PCB surface
  3. Test UART interface connectivity
    Connect a USB-to-serial adapter (configured at common baud rates such as 115200, 57600, 9600) to the suspected UART pads (TX, RX, GND) and power on the device to observe if a console prompt or boot messages appear
    Affected if The UART interface responds with readable console output or provides shell access without any authentication prompt
  4. Verify boot sequence authentication
    Attempt to interact with the UART console during device startup to determine if the boot process requires any password, PIN, or authentication before providing shell or configuration access
    Affected if The device provides shell or configuration access immediately upon UART connection without requiring any credentials or user interaction
  5. Check for physical hardening measures
    Examine the UART pads and surrounding PCB area for signs of conformal coating, potting compound, or physical obstruction that would prevent direct access to the interface
    Affected if The UART pads are exposed without protective coating, potting, or physical barriers preventing direct contact

You are affected if your WDR201A device (HW V2.1, FW LFMZX28040922V1.02) has accessible UART pads on the PCB that provide unauthenticated console or shell access when connected with a serial adapter.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Physical security controls (enclosure locking, tamper-evident seals) should be implemented; additionally, UART console access should be disabled or password-protected in firmware if possible.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-30704 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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