What is the CVSS score of CVE-2020-6990?

CVE-2020-6990 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.1%.

Rslogix 500 CVE-2020-6990

CRITICAL

Use of Hard-coded Cryptographic Key (CWE-321)

2020-03-16 ics-cert@hq.dhs.gov

Authentication Bypass Rockwell Micrologix 1100 Firmware Micrologix 1400 A Firmware Micrologix 1400 B Firmware Rslogix 500 Rockwellautomation

9.8

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-321 OWASP Top 10:2025 A04:2025 - Cryptographic Failures ASVS 5.0 V11 - Cryptography Key management, no hard-coded keys
Impact	CVSS score of 9.8 (CRITICAL). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. EPSS exploitation probability: 0.15%.
Exploit ScenarioDerived	This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the critical-severity affected system.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.

No patch listed yet 0.1% exploitation probability (EPSS)

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AnalysisAI

Rockwell Automation MicroLogix 1400 Controllers Series B v21.001 and prior, Series A, all versions, MicroLogix 1100 Controller, all versions, RSLogix 500 Software v12.001 and prior, The cryptographic. Rated critical severity (CVSS 9.8), 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. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

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Technical ContextAI · show details

This vulnerability is classified under CWE-321. Rockwell Automation MicroLogix 1400 Controllers Series B v21.001 and prior, Series A, all versions, MicroLogix 1100 Controller, all versions, RSLogix 500 Software v12.001 and prior, The cryptographic key utilized to help protect the account password is hard coded into the RSLogix 500 binary file. An attacker could identify cryptographic keys and use it for further cryptographic attacks that could ultimately lead to a remote attacker gaining unauthorized access to the controller. Affected products include: Rockwellautomation Micrologix 1400 A Firmware, Rockwellautomation Micrologix 1400 B Firmware, Rockwellautomation Micrologix 1100 Firmware, Rockwellautomation Rslogix 500.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 9.8 CRITICAL

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

High

Integrity

High

Availability

High

DescriptionCVE.org

Rockwell Automation MicroLogix 1400 Controllers Series B v21.001 and prior, Series A, all versions, MicroLogix 1100 Controller, all versions, RSLogix 500 Software v12.001 and prior, The cryptographic key utilized to help protect the account password is hard coded into the RSLogix 500 binary file. An attacker could identify cryptographic keys and use it for further cryptographic attacks that could ultimately lead to a remote attacker gaining unauthorized access to the controller.

Threat Intelligence Overview

EPSS Score

0.1%

Top 65% 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 CRITICAL

CISA KEV No

Public POC No

EPSS 0.1%

Patch available No

Active threat No

Deciding rule

CRITICAL severity

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.