CVE-2020-7566

Name: CVE-2020-7566
Creator: NVD / NIST
Published: 2020-11-19T22:15:15.02+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.3/10EPSS 0.29%

Last modified Jun 17, 2026

CVE-2020-7566 is a high-severity vulnerability rated 7.3/10 on the CVSS scale. A CWE-334: Small Space of Random Values vulnerability exists in Modicon M221 (all references, all versions) that could allow the attacker to break the encryption keys when the attacker has captured the traffic between EcoStruxure Machine - Basic software and Modicon M221 controller.. EPSS estimates a 0.29% chance of exploitation in the next 30 days.

Description

A CWE-334: Small Space of Random Values vulnerability exists in Modicon M221 (all references, all versions) that could allow the attacker to break the encryption keys when the attacker has captured the traffic between EcoStruxure Machine - Basic software and Modicon M221 controller.

Metrics

CVSS 3.1

7.3/10

CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

EPSS Probability

0.29%

20.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-334

Affected Software

Vendor	Product	Versions
Schneider-Electric	Modicon M221 Firmware	All versions

References

https://us-cert.cisa.gov/ics/advisories/icsa-20-343-04Third Party Advisory, US Government Resource
https://www.se.com/ww/en/download/document/SEVD-2020-315-05/Vendor Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-20-343-04Third Party Advisory, US Government Resource
https://www.se.com/ww/en/download/document/SEVD-2020-315-05/Vendor Advisory

Timeline

Published: Nov 19, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-7566?

How severe is CVE-2020-7566?

CVE-2020-7566 has a CVSS score of 7.3/10 (HIGH severity). The EPSS model estimates a 0.29% probability of exploitation in the next 30 days.

How do I fix CVE-2020-7566?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-7566?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST