CVE-2020-6990
CRITICALEPSS 90th pctlDescription
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.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
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CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
High risk: more likely to be exploited than 90% of all known CVEs.
References
Related Vulnerabilities
Other CWE-321 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2025-30406 | Critical | 9.0 | 94% | KEV | Fix |
| CVE-2016-4437 | Critical | 9.8 | 93% | KEV | Fix |
| CVE-2023-32169 | Critical | 9.8 | 56% | - | - |
| CVE-2023-27584 | Critical | 9.8 | 34% | - | Fix |
| CVE-2020-10884 | High | 8.8 | 25% | - | - |
| CVE-2021-4228 | Medium | 5.8 | 9.9% | - | - |
Common questions
How do I fix CVE-2020-6990?
No published fix for CVE-2020-6990 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2020-6990 being actively exploited?
Not that we know of. CVE-2020-6990 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 4.4% is the estimated probability that it will be exploited in the next 30 days. That is higher than 90% of all scored CVEs.
How severe is CVE-2020-6990?
CVE-2020-6990 has a CVSS v3 base score of 9.8, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-03.