CVE-2021-20598

Name: CVE-2021-20598
Creator: NVD / NIST
Published: 2021-08-06T17:15:07.173+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.3/10EPSS 1.51%

Last modified Jun 17, 2026

CVE-2021-20598 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. Overly Restrictive Account Lockout Mechanism vulnerability in Mitsubishi Electric MELSEC iQ-R series CPU modules (R08/16/32/120SFCPU all versions, R08/16/32/120PSFCPU all versions) allows a remote unauthenticated attacker to lockout a legitimate user by continuously trying login with incorrect password.. EPSS estimates a 1.51% chance of exploitation in the next 30 days.

Description

Overly Restrictive Account Lockout Mechanism vulnerability in Mitsubishi Electric MELSEC iQ-R series CPU modules (R08/16/32/120SFCPU all versions, R08/16/32/120PSFCPU all versions) allows a remote unauthenticated attacker to lockout a legitimate user by continuously trying login with incorrect password.

Metrics

CVSS 3.1

5.3/10

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

EPSS Probability

1.51%

71.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-287

Affected Software

Vendor	Product	Versions
Mitsubishielectric	R08sfcpu Firmware	All versions
Mitsubishielectric	R16sfcpu Firmware	All versions
Mitsubishielectric	R32sfcpu Firmware	All versions
Mitsubishielectric	R120sfcpu Firmware	All versions
Mitsubishielectric	R08psfcpu Firmware	All versions
Mitsubishielectric	R16psfcpu Firmware	All versions
Mitsubishielectric	R32psfcpu Firmware	All versions
Mitsubishielectric	R120psfcpu Firmware	All versions

References

https://jvn.jp/vu/JVNVU98578731/index.htmlThird Party Advisory
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-010_en.pdfVendor Advisory
https://jvn.jp/vu/JVNVU98578731/index.htmlThird Party Advisory
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-010_en.pdfVendor Advisory

Timeline

Published: Aug 6, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20598?

How severe is CVE-2021-20598?

CVE-2021-20598 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 1.51% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20598?

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-2021-20598?

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

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Source: NVD / NIST