Smart FirewallApplication · Getcujo

CVE-2018-4031

CRITICAL · 10.0 CVSS v3.1 Published 2019-10-31
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
An exploitable vulnerability exists in the safe browsing function of the CUJO Smart Firewall, version 7003. The flaw lies in the way the safe browsing function parses HTTP requests. The server hostname is extracted from captured HTTP/HTTPS requests and inserted as part of a Lua statement without prior sanitization, which results in arbitrary Lua script execution in the kernel. An attacker could send an HTTP request to exploit this vulnerability.

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 CUJO Smart Firewall version 7003 safe browsing function extracts server hostnames from captured HTTP/HTTPS requests and directly inserts them into Lua statements without sanitization, allowing arbitrary Lua script execution in the kernel.

MitigationApply the vendor-supplied firmware patch when available; until then, consider disabling the safe browsing function or isolating the device from 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
Smart FirewallApplication
Affected:= 7003

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
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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
    Confirm the device is a CUJO Smart Firewall by checking the device label or administrative interface for the model name
    Affected if Device is not a CUJO Smart Firewall, then not affected by this specific CVE
  2. Check the firmware version
    Access the device administrative interface or check via CLI/API to determine the installed firmware version
    Affected if Firmware version is NOT 7003, then not vulnerable (this CVE affects only version 7003 exactly)
  3. Locate the safe browsing setting
    Navigate to the device settings or configuration panel to find the safe browsing or content filtering function
    Affected if Cannot locate safe browsing function, then likely not vulnerable to this specific attack vector
  4. Verify if safe browsing is enabled
    Check the safe browsing configuration status in the device settings or via CLI command if available
    Affected if Safe browsing is disabled, then the attack surface for this specific vulnerability is not present

Device is affected only if it is a CUJO Smart Firewall running firmware version 7003 with the safe browsing function enabled.

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

Apply the vendor-supplied firmware patch when available; until then, consider disabling the safe browsing function or isolating the device from untrusted networks.

Fix this in Smart Firewall Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

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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-2018-4031 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