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Command InjectionWeakness · CWE-77

CVE-2026-11556

HIGH · 8.8 CVSS v3.1 Published 2026-06-08
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable 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 flaw has been discovered in Tenda F451 1.0.0.7/1.0.0.9. Impacted is the function formWriteFacMac of the file /goform/WriteFacMac of the component Web Management Interface. Performing a manipulation of the argument mac results in os command injection. Remote exploitation of the attack is possible. The exploit has been released to the public and may be used for attacks.

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

OS command injection vulnerability in Tenda F451 router's web management interface (/goform/WriteFacMac). The formWriteFacMac function fails to sanitize the 'mac' parameter, allowing attackers to inject arbitrary OS commands via the web interface. Exploitable remotely with publicly available exploit code.

MitigationImmediately restrict access to the router's web management interface from untrusted networks (do not expose to internet). Contact Tenda for firmware updates addressing this command injection, or implement network segmentation as a compensating control until patch is available.

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/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 device model
    Access the router's web interface or check the device label/menu for the exact model number to confirm it is a Tenda F451
    Affected if The device is a Tenda F451 router
  2. Confirm web management interface is accessible
    Attempt to reach the router's web interface over HTTP/HTTPS (typically ports 80 or 443) from the network
    Affected if The web management interface is exposed and reachable
  3. Check if vulnerable endpoint exists
    Send a request to /goform/WriteFacMac and observe if the endpoint responds (even with an error)
    Affected if The /goform/WriteFacMac endpoint is present and responds to requests
  4. Verify mac parameter is accepted
    Submit a request to /goform/WriteFacMac with a test value in the 'mac' parameter and check if the application processes it
    Affected if The 'mac' parameter is accepted and processed by the endpoint

If the device is a Tenda F451 with an accessible web interface and the /goform/WriteFacMac endpoint responds to the 'mac' parameter, the environment is affected by this vulnerability.

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 restrict access to the router's web management interface from untrusted networks (do not expose to internet). Contact Tenda for firmware updates addressing this command injection, or implement network segmentation as a compensating control until patch is available.

Recommended fix Moderate confidence

Latest firmware version available from Tenda (check www.tenda.com.cn for F451 v1.0.0.10 or higher)

  1. 1. Check Tenda's official support website (www.tenda.com.cn) for the latest firmware version for the F451 router.
  2. 2. Download the latest firmware update that addresses security vulnerabilities.
  3. 3. Access the router's web management interface at its local IP address.
  4. 4. Navigate to the firmware upgrade or system settings section.
  5. 5. Upload and apply the new firmware version.
  6. 6. After upgrade, verify the /goform/WriteFacMac functionality works correctly and the vulnerability is remediated.
  7. 7. If no official firmware is available, consider placing the device behind a firewall with restricted access to the web management interface.
Caveat firmware upgrades may reset router configuration to defaults; backup current settings before upgrading

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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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-2026-11556 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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