CVE-2020-12523 | Phoenix Contact mGuard Devices versions before 8.8.3: LAN ports get functional after reboot even if they are disabled in the device configuration

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

Published: 2020-12-17 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-12523 is rated Moderate Risk (41.2/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.89%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-12523

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.38% 0.89% +0.51%
2 2025-03-30 0.73% 0.38% -0.36%
3 2025-03-29 — 0.73% —

Full EPSS history (9 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-12523

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.4 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 2.8 2.5 [email protected]
9.1 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.2 [email protected]
6.4 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 4.9 [email protected]

Weakness enumeration for CVE-2020-12523

Affected software / configurations for CVE-2020-12523

Vendor Product Version Raw CPE
phoenixcontact tc_mguard_rs4000_4g_vzw_vpn_firmware < 8.8.3 cpe:2.3:o:phoenixcontact:tc_mguard_rs4000_4g_vzw_vpn_firmware:*:*:*:*:*:*:*:*
phoenixcontact tc_mguard_rs4000_4g_att_vpn_firmware < 8.8.3 cpe:2.3:o:phoenixcontact:tc_mguard_rs4000_4g_att_vpn_firmware:*:*:*:*:*:*:*:*
phoenixcontact fl_mguard_rs4004_tx\/dtx_firmware < 8.8.3 cpe:2.3:o:phoenixcontact:fl_mguard_rs4004_tx\/dtx_firmware:*:*:*:*:*:*:*:*
phoenixcontact fl_mguard_rs4004_tx\/dtx_vpn_firmware < 8.8.3 cpe:2.3:o:phoenixcontact:fl_mguard_rs4004_tx\/dtx_vpn_firmware:*:*:*:*:*:*:*:*
phoenixcontact tc_mguard_rs4000_3g_vpn_firmware — cpe:2.3:o:phoenixcontact:tc_mguard_rs4000_3g_vpn_firmware:-:*:*:*:*:*:*:*
phoenixcontact tc_mguard_rs4000_4g_vpn_firmware < 8.8.3 cpe:2.3:o:phoenixcontact:tc_mguard_rs4000_4g_vpn_firmware:*:*:*:*:*:*:*:*
phoenixcontact innominate_mguard_rs4000_4tx\/tx_firmware < 8.8.3 cpe:2.3:o:phoenixcontact:innominate_mguard_rs4000_4tx\/tx_firmware:*:*:*:*:*:*:*:*
phoenixcontact innominate_mguard_rs4000_4tx\/tx_vpn_firmware < 8.8.3 cpe:2.3:o:phoenixcontact:innominate_mguard_rs4000_4tx\/tx_vpn_firmware:*:*:*:*:*:*:*:*
phoenixcontact innominate_mguard_rs4000_4tx\/3g\/tx_vpn_firmware < 8.8.3 cpe:2.3:o:phoenixcontact:innominate_mguard_rs4000_4tx\/3g\/tx_vpn_firmware:*:*:*:*:*:*:*:*

References for CVE-2020-12523

cvelogic Threat Intelligence