CVE-2023-2673Network attack vector

Protected-device flooding via skipped MAC filtering

Published Jun 13, 2023 · Updated Jan 3, 2025

Improper input validation in Phoenix Contact FL/TC MGUARD firmware allows remote attackers to bypass MAC filters with UDP packets. In static or autodetect stealth mode, the forwarding path sends UDP packets addressed to the protected device without applying configured MAC filter rules. The incoming IPv4 filter still blocks traffic by default, multi-stealth mode is unaffected, and reachable traffic can flood the protected device.

CVSS severity5.3
Medium
EPSS probability0.62%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper input validation in Phoenix Contact FL/TC MGUARD firmware allows remote attackers to bypass MAC filters with UDP packets. In static or autodetect stealth mode, the forwarding path sends UDP packets addressed to the protected device without applying configured MAC filter rules. The incoming IPv4 filter still blocks traffic by default, multi-stealth mode is unaffected, and reachable traffic can flood the protected device.

The record

CVE
CVE-2023-2673
Published
Jun 13, 2023
Updated
Jan 3, 2025
Vendor
Phoenix Contact
Product
FL MGUARD RS2000 TX/TX-B
Classifications
CWE-20, CWE-1287, T1498
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 13, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=8.9.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Phoenix Contact · FL MGUARD RS2000 TX/TX-Bversion=0 <=8.9.0
Phoenix Contact · FL MGUARD RS2005 TX VPNversion=0 <=8.9.0
Phoenix Contact · FL MGUARD SMART2version=0 <=8.9.0
Phoenix Contact · FL MGUARD RS4000 TX/TX-Mversion=0 <=8.9.0
Phoenix Contact · FL MGUARD 4102 PCIEversion=0 <=10.1.1
Phoenix Contact · FL MGUARD RS4004 TX/DTXversion=0 <=8.9.0
Phoenix Contact · FL MGUARD PCIE4000version=0 <=8.9.0
Phoenix Contact · FL MGUARD RS4000 TX/TX-Pversion=0 <=8.9.0
Phoenix Contact · FL MGUARD PCIE4000 VPNversion=0 <=8.9.0
Phoenix Contact · FL MGUARD 4302version=0 <=10.1.1
Phoenix Contact · FL MGUARD RS4004 TX/DTX VPNversion=0 <=8.9.0
Phoenix Contact · FL MGUARD SMART2 VPNversion=0 <=8.9.0
Phoenix Contact · FL MGUARD CORE TXversion=0 <=8.9.0
Phoenix Contact · FL MGUARD CORE TX VPNversion=0 <=8.9.0
Phoenix Contact · FL MGUARD 4102 PCIversion=0 <=10.1.1
Phoenix Contact · FL MGUARD RS4000 TX/TX VPNversion=0 <=8.9.0
Phoenix Contact · FL MGUARD CENTERPORT VPN-1000version=0 <=8.9.0
Phoenix Contact · FL MGUARD DELTA TX/TXversion=0 <=8.9.0
Phoenix Contact · FL MGUARD PCI4000version=0 <=8.9.0
Phoenix Contact · FL MGUARD 2102version=0 <=10.1.1
Phoenix Contact · FL MGUARD GT/GTversion=0 <=8.9.0
Phoenix Contact · FL MGUARD CENTERPORTversion=0 <=8.9.0
Phoenix Contact · FL MGUARD PCI4000 VPNversion=0 <=8.9.0
Phoenix Contact · FL MGUARD GT/GT VPNversion=0 <=8.9.0
Phoenix Contact · FL MGUARD RS2000 TX/TX VPNversion=0 <=8.9.0
Phoenix Contact · FL MGUARD DELTA TX/TX VPNversion=0 <=8.9.0

Published CVSS scores

5.8Phoenix ContactCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
5.3CERT@VDE CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-1287Improper Validation of Specified Type of Input
T1498Network Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo