CVE-2021-20612

Name: CVE-2021-20612
Creator: NVD / NIST
Published: 2022-01-14T20:15:09.85+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 3.60%

Last modified Jun 17, 2026

CVE-2021-20612 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Lack of administrator control over security vulnerability in MELSEC-F series FX3U-ENET Firmware version 1.14 and prior, FX3U-ENET-L Firmware version 1.14 and prior and FX3U-ENET-P502 Firmware version 1.14 and prior allows a remote unauthenticated attacker to cause a denial-of-service (DoS) condition in communication function of the product or other unspecified effects by sending specially crafted packets to an unnecessary opening of TCP port. Control by MELSEC-F series PLC is not affected by this vulnerability, but system reset is required for recovery.. EPSS estimates a 3.60% chance of exploitation in the next 30 days.

Description

Lack of administrator control over security vulnerability in MELSEC-F series FX3U-ENET Firmware version 1.14 and prior, FX3U-ENET-L Firmware version 1.14 and prior and FX3U-ENET-P502 Firmware version 1.14 and prior allows a remote unauthenticated attacker to cause a denial-of-service (DoS) condition in communication function of the product or other unspecified effects by sending specially crafted packets to an unnecessary opening of TCP port. Control by MELSEC-F series PLC is not affected by this vulnerability, but system reset is required for recovery.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

3.60%

88.0th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Mitsubishielectric	Fx3u-Enet Firmware	<= 1.14
Mitsubishielectric	Fx3u-Enet-L Firmware	<= 1.14
Mitsubishielectric	Fx3u-Enet-P502 Firmware	<= 1.14

References

https://jvn.jp/vu/JVNVU93268332/index.htmlThird Party Advisory, VDB Entry
https://www.cisa.gov/uscert/ics/advisories/icsa-22-013-01Third Party Advisory, US Government Resource
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-023_en.pdfVendor Advisory
https://jvn.jp/vu/JVNVU93268332/index.htmlThird Party Advisory, VDB Entry
https://www.cisa.gov/uscert/ics/advisories/icsa-22-013-01Third Party Advisory, US Government Resource
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-023_en.pdfVendor Advisory

Timeline

Published: Jan 14, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20612?

How severe is CVE-2021-20612?

CVE-2021-20612 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 3.60% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20612?

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-2021-20612?

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

Scan your code now

Source: NVD / NIST