CVE-2021-20600

Name: CVE-2021-20600
Creator: NVD / NIST
Published: 2021-10-08T17:15:07.437+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.9/10EPSS 2.24%

Last modified Jun 17, 2026

CVE-2021-20600 is a medium-severity vulnerability rated 5.9/10 on the CVSS scale. Uncontrolled resource consumption in Mitsubishi Electric MELSEC iQ-R series C Controller Module R12CCPU-V Firmware Versions "16" and prior allows a remote unauthenticated attacker to cause a denial-of-service (DoS) condition by sending a large number of packets in a short time while the module starting up. System reset is required for recovery.. EPSS estimates a 2.24% chance of exploitation in the next 30 days.

Description

Uncontrolled resource consumption in Mitsubishi Electric MELSEC iQ-R series C Controller Module R12CCPU-V Firmware Versions "16" and prior allows a remote unauthenticated attacker to cause a denial-of-service (DoS) condition by sending a large number of packets in a short time while the module starting up. System reset is required for recovery.

Metrics

CVSS 3.1

5.9/10

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

EPSS Probability

2.24%

80.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-400

Affected Software

Vendor	Product	Versions
Mitsubishielectric	R12ccpu-V Firmware	<= 16

References

https://jvn.jp/vu/JVNVU94914666/index.htmlThird Party Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-21-280-04Third Party Advisory, US Government Resource
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-015_en.pdfVendor Advisory
https://jvn.jp/vu/JVNVU94914666/index.htmlThird Party Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-21-280-04Third Party Advisory, US Government Resource
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-015_en.pdfVendor Advisory

Timeline

Published: Oct 8, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20600?

How severe is CVE-2021-20600?

CVE-2021-20600 has a CVSS score of 5.9/10 (MEDIUM severity). The EPSS model estimates a 2.24% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20600?

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-2021-20600?

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

Scan your code now

Source: NVD / NIST