Fh303 FirmwareOperating system · Tenda

CVE-2018-25318

CRITICAL · 9.8 CVSS v3.1 Published 2026-04-29
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
Public exploit 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
Tenda FH303/A300 firmware V5.07.68_EN contains a session weakness vulnerability that allows unauthenticated attackers to modify DNS settings by exploiting insufficient cookie validation. Attackers can send GET requests to the /goform/AdvSetDns endpoint with a crafted admin cookie to change DNS servers and redirect user traffic to malicious sites.

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 Tenda FH303/A300 router firmware V5.07.68_EN contains a session weakness vulnerability where the /goform/AdvSetDns endpoint fails to properly validate cookie credentials. Attackers can send unauthenticated GET requests with a crafted admin cookie to modify DNS server settings, enabling traffic redirection to malicious sites.

MitigationUpgrade the router firmware to a patched version if available; if no update exists, disable remote administration interfaces or implement network segmentation to limit exposure to untrusted networks.

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
Fh303 FirmwareOperating system
Affected:= 5.07.68_en
A300 FirmwareOperating system
Affected:= 5.07.68_en

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
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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 router model
    Check the device label or admin interface to confirm the model is Tenda FH303 or Tenda A300
    Affected if Model is FH303 or A300
  2. Check installed firmware version
    Access router admin panel or use `telnet`/`ssh` if enabled to retrieve firmware version; typical path is Status or Administration page
    Affected if Firmware version equals 5.07.68_en exactly
  3. Verify if remote administration is enabled
    In router admin panel, check Remote Management or Remote Access settings (typically under Advanced or Administration tabs)
    Affected if Remote administration/remote management is enabled and accessible from WAN
  4. Confirm DNS configuration is not manipulated
    In router admin panel, go to Advanced Settings or Network Settings and inspect Primary DNS and Secondary DNS fields under WAN or DHCP settings
    Affected if DNS servers point to unexpected or attacker-controlled IP addresses or DNS settings have been changed without admin action
  5. Test vulnerable endpoint accessibility
    From an external network, attempt to access http://[router WAN IP]/goform/AdvSetDns via GET request with crafted cookie headers
    Affected if Endpoint responds without requiring valid authentication (indicates session validation flaw is exploitable)

A user is affected if they run exactly firmware version 5.07.68_en on an FH303 or A300 router and the router admin interface is accessible (locally or remotely), allowing the DNS settings to be modified without proper authentication.

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

Upgrade the router firmware to a patched version if available; if no update exists, disable remote administration interfaces or implement network segmentation to limit exposure to untrusted networks.

Fix this in Fh303 Firmware Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,980
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2018-25318 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-25318 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data