Skip to content
Fencer Intel
critical 9.1

CVE-2021-20597 json

Insufficiently Protected Credentials vulnerability in Mitsubishi Electric MELSEC iQ-R series Safety CPU modules R08/16/32/120SFCPU firmware…

published 5y ago modified 4mo ago also EUVD-2021-8015

cvss
9.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.2%
EPSS 2.2% chance of exploitation in 30 days, percentile 82%
public exploits
0
none known

Summary

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.

Is CVE-2021-20597 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-21-250-01 updated cvss 7.4

Mitsubishi Electric MELSEC iQ-R Series

  • Mitsubishi Electric Corporation MELSEC iQ-R series Safety CPU R08SFCPU Firmware <=26 Mitsubishi Electric Corporation MELSEC iQ-R series Safety CPU R16SFCPU Firmware <=26 Mitsubishi Electric Corporation MELSEC iQ-R series Safety CPU R32SFCPU Firmware <=26 Mitsubishi Electric Corporation MELSEC iQ-R series Safety CPU R120SFCPU Firmware <=26 Mitsubishi Electric Corporation MELSEC iQ-R series SIL2 Process CPU R08PSFCPU Firmware <=11 Mitsubishi Electric Corporation MELSEC iQ-R series SIL2 Process CPU R16PSFCPU Firmware <=11
    +2 more products
    Mitsubishi Electric Corporation MELSEC iQ-R series SIL2 Process CPU R32PSFCPU Firmware <=11 Mitsubishi Electric Corporation MELSEC iQ-R series SIL2 Process CPU R120PSFCPU Firmware <=11
    affected: mitigation “MELSEC iQ-R series Safety CPU R08/16/32/120SFCPU:Firmware versions "27" or later” mitsubishifa.co.th

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

Exploit prediction

2.22% chance of exploitation in the next 30 days, higher than 82% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:P/I:P/A:N

Affected products

  • n/a Mitsubishi Electric MELSEC iQ-R series Safety CPU modules R08/16/32/120SFCPU; Mitsubishi Electric MELSEC iQ-R series SIL2 Process CPU modules R08/16/32/120PSFCPU

Classification

Weakness
  • CWE-522 Insufficiently Protected Credentials

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.