HOMEVULNERABILITIESCVE-2020-12523
CRITICAL

CVE-2020-12523

CWE-909Published: December 17, 2020· Updated: Jun 17, 2026

9.1
CVSS v3.1

Official Description

On Phoenix Contact mGuard Devices versions before 8.8.3 LAN ports get functional after reboot even if they are disabled in the device configuration. For mGuard devices with integrated switch on the LAN side, single switch ports can be disabled by device configuration. After a reboot these ports get functional independent from their configuration setting: Missing Initialization of Resource

NVD Source

Technical Analysis

CVE-2020-12523 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), availability disruption (denial of service), with a CVSS base score of 9.1.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Affected Vendors & Products

phoenixcontact18 product(s)
tc mguard rs4000 4g vzw vpn firmwaretc mguard rs4000 4g vzw vpntc mguard rs4000 4g att vpn firmwaretc mguard rs4000 4g att vpnfl mguard rs4004 tx\/dtx firmwarefl mguard rs4004 tx\/dtxfl mguard rs4004 tx\/dtx vpn firmwarefl mguard rs4004 tx\/dtx vpntc mguard rs4000 3g vpn firmwaretc mguard rs4000 3g vpntc mguard rs4000 4g vpn firmwaretc mguard rs4000 4g vpn+6
Source: NVD CPE · 18 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://cert.vde.com/en-us/advisories/vde-2020-046
ADVISORYhttps://cert.vde.com/en-us/advisories/vde-2020-046

All References (2)

→
https://cert.vde.com/en-us/advisories/vde-2020-046Third Party Advisory
→
https://cert.vde.com/en-us/advisories/vde-2020-046Third Party Advisory

Quick Facts

CVE IDCVE-2020-12523
CVSS Score9.1 / 10
SeverityCRITICAL
WeaknessCWE-909
CISA KEVNo
Affected1 vendor(s)
PublishedDec 17, 2020

Related CVEs (CWE-909)

CVE-2022-22704
9.8
CVE-2026-40687
9.1
CVE-2020-11741
8.8
CVE-2021-29980
8.8
CVE-2021-23994
8.8
CVE-2005-1036
7.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2020-12523 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
← All Vulnerabilities·Search for CVE-2020-12523·NVD