CVE-2021-20597

Name: CVE-2021-20597
Creator: NVD / NIST
Published: 2021-08-06T17:15:07.14+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.1/10EPSS 2.22%

Last modified Jun 17, 2026

CVE-2021-20597 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. Insufficiently Protected Credentials vulnerability in Mitsubishi Electric MELSEC iQ-R series Safety CPU modules R08/16/32/120SFCPU firmware versions "26" and prior and Mitsubishi Electric MELSEC iQ-R series SIL2 Process CPU modules R08/16/32/120PSFCPU firmware versions "11" and prior allows a remote unauthenticated attacker to login to the target unauthorizedly by sniffing network traffic and obtaining credentials when registering user information in the target or changing a password.. EPSS estimates a 2.22% chance of exploitation in the next 30 days.

Description

Insufficiently Protected Credentials vulnerability in Mitsubishi Electric MELSEC iQ-R series Safety CPU modules R08/16/32/120SFCPU firmware versions "26" and prior and Mitsubishi Electric MELSEC iQ-R series SIL2 Process CPU modules R08/16/32/120PSFCPU firmware versions "11" and prior allows a remote unauthenticated attacker to login to the target unauthorizedly by sniffing network traffic and obtaining credentials when registering user information in the target or changing a password.

Metrics

CVSS 3.1

9.1/10

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

EPSS Probability

2.22%

80.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-522

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.cisa.gov/uscert/ics/advisories/icsa-21-250-01
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-009_en.pdfVendor Advisory
https://jvn.jp/vu/JVNVU98578731/index.htmlThird Party Advisory
https://www.cisa.gov/uscert/ics/advisories/icsa-21-250-01
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-009_en.pdfVendor Advisory

Timeline

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

Frequently Asked Questions

What is CVE-2021-20597?

How severe is CVE-2021-20597?

CVE-2021-20597 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 2.22% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20597?

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-2021-20597?

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

Scan your code now

Source: NVD / NIST