What is the CVSS score of CVE-2019-6820?

CVE-2019-6820 has a CVSS 3.1 base score of 8.2 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H. EPSS exploitation probability: 0.3%.

Modicon M251 Firmware CVE-2019-6820

HIGH

Missing Authentication for Critical Function (CWE-306)

2019-05-22 cybersecurity@se.com

Authentication Bypass Schneider Electric Modicon M251 Firmware Modicon M241 Firmware Modicon M221 Firmware Modicon M100 Firmware Modicon M200 Firmware Atv Imc Drive Controller Firmware Modicon M258 Firmware Modicon Lmc058 Firmware Modicon Lmc078 Firmware Pacdrive Eco Firmware Pacdrive Pro Firmware Pacdrive Pro2 Firmware

8.2

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-306 OWASP Top 10:2025 A07:2025 - Authentication Failures ASVS 5.0 V6 - Authentication Authentication required for critical functions MITRE ATT&CK 1 technique across 1 tactic: Initial Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS score of 8.2 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. EPSS exploitation probability: 0.30%.
Exploit ScenarioDerived	A remote attacker could access critical functionality without authentication by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

No patch listed yet 0.3% exploitation probability (EPSS)

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AnalysisAI

A CWE-306: Missing Authentication for Critical Function vulnerability exists which could cause a modification of device IP configuration (IP address, network mask and gateway IP address) when a. Rated high severity (CVSS 8.2), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Require authentication for all sensitive operations, implement defense in depth.

Affects your stack

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Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Missing Authentication for Critical Function (CWE-306), which allows attackers to access critical functionality without authentication. A CWE-306: Missing Authentication for Critical Function vulnerability exists which could cause a modification of device IP configuration (IP address, network mask and gateway IP address) when a specific Ethernet frame is received in all versions of: Modicon M100, Modicon M200, Modicon M221, ATV IMC drive controller, Modicon M241, Modicon M251, Modicon M258, Modicon LMC058, Modicon LMC078, PacDrive Eco ,PacDrive Pro, PacDrive Pro2 Affected products include: Schneider-Electric Modicon M100 Firmware, Schneider-Electric Modicon M200 Firmware, Schneider-Electric Modicon M221 Firmware, Schneider-Electric Atv Imc Drive Controller Firmware, Schneider-Electric Modicon M241 Firmware.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 8.2 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

High

DescriptionCVE.org

A CWE-306: Missing Authentication for Critical Function vulnerability exists which could cause a modification of device IP configuration (IP address, network mask and gateway IP address) when a specific Ethernet frame is received in all versions of: Modicon M100, Modicon M200, Modicon M221, ATV IMC drive controller, Modicon M241, Modicon M251, Modicon M258, Modicon LMC058, Modicon LMC078, PacDrive Eco ,PacDrive Pro, PacDrive Pro2

Threat Intelligence Overview

EPSS Score

0.3%

Top 46% exploitable

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS

VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity HIGH

CISA KEV No

Public POC No

EPSS 0.3%

Patch available No

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

None

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +41

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Authentication Bypass CRITICAL

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Affected Products (CPE)CVE.org

cpe:2.3:o:schneider-electric:modicon_m100_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:schneider-electric:modicon_m200_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:schneider-electric:modicon_m221_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:schneider-electric:atv_imc_drive_controller_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:schneider-electric:modicon_m241_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:schneider-electric:modicon_m251_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:schneider-electric:modicon_m258_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:schneider-electric:modicon_lmc058_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:schneider-electric:modicon_lmc078_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:schneider-electric:pacdrive_eco_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:schneider-electric:pacdrive_pro_firmware:*:*:*:*:*:*:*:*

cpe:2.3:o:schneider-electric:pacdrive_pro2_firmware:*:*:*:*:*:*:*:*

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References

Advisories & patches

ADVISORY https://vuldb.com/vuln/135379 ADVISORY https://www.schneider-electric.com/en/download/document/SEVD-2019-134-02/

Search Externally

GitHub PoC

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