CVE-2021-20599

Name: CVE-2021-20599
Creator: NVD / NIST
Published: 2021-10-14T15:15:08.827+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 1.30%

Last modified Jun 17, 2026

CVE-2021-20599 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Cleartext Transmission of Sensitive InformationCleartext transmission of sensitive information vulnerability in MELSEC iQ-R series Safety CPU R08/16/32/120SFCPU firmware versions "26" and prior and MELSEC iQ-R series SIL2 Process CPU R08/16/32/120PSFCPU firmware versions "11" and prior allows a remote unauthenticated attacker to login to a target CPU module by obtaining credentials other than password.. EPSS estimates a 1.30% chance of exploitation in the next 30 days.

Description

Cleartext Transmission of Sensitive InformationCleartext transmission of sensitive information vulnerability in MELSEC iQ-R series Safety CPU R08/16/32/120SFCPU firmware versions "26" and prior and MELSEC iQ-R series SIL2 Process CPU R08/16/32/120PSFCPU firmware versions "11" and prior allows a remote unauthenticated attacker to login to a target CPU module by obtaining credentials other than password.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

1.30%

66.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

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/JVNVU98578731Third Party Advisory
https://www.cisa.gov/uscert/ics/advisories/icsa-21-287-03
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-011_en.pdfVendor Advisory
https://jvn.jp/vu/JVNVU98578731Third Party Advisory
https://www.cisa.gov/uscert/ics/advisories/icsa-21-287-03
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-011_en.pdfVendor Advisory

Timeline

Published: Oct 14, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20599?

How severe is CVE-2021-20599?

CVE-2021-20599 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.30% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20599?

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-2021-20599?

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

Scan your code now

Source: NVD / NIST