dbcve.org
W12 FirmwareOperating system · Tenda

CVE-2025-9778

HIGH · 7.0 CVSS v3.1 Published 2025-09-01
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
72/100
Remediation priority · Elevated
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
A security vulnerability has been detected in Tenda W12 up to 3.0.0.6(3948). Affected is an unknown function of the file /etc_ro/shadow of the component Administrative Interface. The manipulation leads to hard-coded credentials. An attack has to be approached locally. The complexity of an attack is rather high. The exploitability is told to be difficult. The exploit has been disclosed publicly and may be used.

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 · moderate confidence

The Tenda W12 router up to version 3.0.0.6(3948) contains hard-coded credentials stored in the /etc_ro/shadow file of its Administrative Interface component. This vulnerability requires local access to exploit and has high complexity with difficult exploitability, but the hard-coded credentials may provide unauthorized access to the device's admin functions.

MitigationImmediately change any default administrative credentials on affected devices, apply available firmware updates, and restrict physical and local network access to the device's administrative interface to reduce the attack surface.

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
W12 FirmwareOperating system
Affected:= 3.0.0.6\(3948\)

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
Local
Complexity
High
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/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 the router model
    Check the device label or admin interface to confirm the model is Tenda W12
    Affected if Device is not a Tenda W12 router - not affected
  2. Determine the firmware version
    Access the router's administrative interface (typically via web browser at 192.168.0.1 or similar) and navigate to System Settings or Firmware Upgrade to find the installed version, or use the router's console/telnet/ssh if available to run 'cat /proc/version' or check /etc_ro/lighttpd.conf or similar version files
    Affected if Firmware version is higher than 3.0.0.6(3948) - not affected; version 3.0.0.6(3948) or below - potentially affected
  3. Locate the shadow file
    Access the router's file system via console, telnet, SSH, or by extracting the firmware binary and navigate to /etc_ro/shadow
    Affected if File /etc_ro/shadow does not exist on the device - not applicable to this CVE
  4. Inspect for hard-coded credentials
    Examine the contents of /etc_ro/shadow for any hardcoded password hashes, particularly looking for credentials that are not user-defined or that appear in the default configuration. Compare any found credentials against known default or hardcoded values for this device.
    Affected if Hard-coded credentials are present in /etc_ro/shadow that differ from user-created admin accounts - affected

The device is affected if it is a Tenda W12 router running firmware version 3.0.0.6(3948) or earlier, and the /etc_ro/shadow file contains hard-coded credentials that provide unauthorized administrative access.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Immediately change any default administrative credentials on affected devices, apply available firmware updates, and restrict physical and local network access to the device's administrative interface to reduce the attack surface.

Recommended fix Moderate confidence

Latest Tenda W12 firmware version available from www.tenda.com.cn (version > 3.0.0.6(3948))

  1. 1. Identify the current firmware version of the Tenda W12 device by accessing the administrative interface or checking the device label
  2. 2. Navigate to the official Tenda support page at www.tenda.com.cn and locate the W12 product firmware download section
  3. 3. Download the latest available firmware version for the W12 router (version higher than 3.0.0.6(3948))
  4. 4. Access the Tenda W12 administrative interface, typically via web browser at 192.168.0.1 or 192.168.1.1
  5. 5. Navigate to the Firmware Upgrade or System Settings section
  6. 6. Upload and apply the downloaded firmware file, allowing the device to reboot
  7. 7. After upgrade, access the administrative interface and immediately change the default administrator password from any hardcoded/default credentials to a strong, unique password
  8. 8. Verify the firmware version has been updated successfully
Caveat Minor: After firmware upgrade, reconfigure wireless settings and any custom port forwards as these may reset to defaults

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in W12 Firmware Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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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-2025-9778 in production — separate from our analysis above.

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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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data