Fl Nat Smn 8tx M Dmg FirmwareOperating system · Phoenixcontact

CVE-2019-9744

HIGH · 8.8 CVSS v3.0 Published 2019-03-26
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges

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 issue was discovered on PHOENIX CONTACT FL NAT SMCS 8TX, FL NAT SMN 8TX, FL NAT SMN 8TX-M, and FL NAT SMN 8TX-M-DMG devices. There is unauthorized access to the WEB-UI by attackers arriving from the same source IP address as an authenticated user, because this IP address is used as a session identifier.

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 Phoenix Contact FL NAT devices use the client source IP address as the sole session identifier for web UI authentication. An attacker sharing the same IP address (e.g., behind NAT, on same network, or via IP spoofing) can impersonate any currently authenticated user and gain unauthorized access to the web interface.

MitigationReplace IP-based session management with cryptographically random session tokens; until a vendor firmware patch is available, restrict web UI access to isolated networks or VPN-only connections.

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
Fl Nat Smn 8tx M Dmg FirmwareOperating system
Affected:all versions
Fl Nat Smn 8tx M FirmwareOperating system
Affected:all versions
Fl Nat Smn 8tx FirmwareOperating system
Affected:all versions
Fl Nat Smcs 8tx FirmwareOperating system
Affected:all versions

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
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:R/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 device web UI or CLI and retrieve the exact product model name (e.g., FL NAT SMN 8TX, FL NAT SMN 8TX M, FL NAT SMN 8TX M DMG, or FL NAT SMCS 8TX)
    Affected if The model matches one of the affected products: FL NAT SMN 8TX M DMG, FL NAT SMN 8TX M, FL NAT SMN 8TX, or FL NAT SMCS 8TX
  2. Confirm firmware version
    Check the device firmware version through the web interface (typically under System > Firmware or Status page) or via CLI command
    Affected if All firmware versions of the affected models are vulnerable; any version found confirms exposure
  3. Verify web UI is enabled
    Attempt to access the device web interface via HTTP/HTTPS on the configured management IP address
    Affected if The web UI is accessible and responds to authentication requests, enabling the attack vector
  4. Check network exposure
    Determine if the device web UI is accessible from networks where multiple clients share the same source IP address (e.g., behind NAT, on a shared LAN segment, or exposed to untrusted networks)
    Affected if The web UI is reachable from behind a NAT gateway, from a shared network segment, or from any network where other devices or users can source traffic with a potentially shared IP address

The environment is affected if a Phoenix Contact FL NAT device (SMN 8TX, SMN 8TX M, SMN 8TX M DMG, or SMCS 8TX) has its web UI accessible from any network where multiple clients can appear with the same source IP address.

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

Replace IP-based session management with cryptographically random session tokens; until a vendor firmware patch is available, restrict web UI access to isolated networks or VPN-only connections.

Fix this in Fl Nat Smn 8tx M Dmg Firmware 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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Scan for this in your stack

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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-2019-9744 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