CVE-2021-20599

mediumpriority · track · 30OT risk · elevatedEPSS 0.014 · 72 %ileEURUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
1.40% (72nd) EPSS
CVSS 5 · medium
Is it mine?
40 products
Check your exposure
Who says so?
4 sources
cnnvd · enisa_euvd · fstec_bdu · cisa_csaf_ot

EPSS · scored 2026-10-27

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.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

No vendor fix yet; a mitigation is available.

  • MitigationMELSEC iQ-R series SIL2 Process CPU R08PSFCPU Firmwarecisa_csaf_ot

    Customers using the affected products and versions may take measures through mitigations and workarounds. Mitsubishi Electric has released the fixed version as shown above, but updating the product to the fixed version is not available. Mitsubishi Electric recommends users take the following mitigation measures to minimize risk associated with this vulnerability:

  • MitigationMELSEC iQ-R series SIL2 Process CPU R120PSFCPU Firmwarecisa_csaf_ot

    Customers using the affected products and versions may take measures through mitigations and workarounds. Mitsubishi Electric has released the fixed version as shown above, but updating the product to the fixed version is not available. Mitsubishi Electric recommends users take the following mitigation measures to minimize risk associated with this vulnerability:

  • MitigationMELSEC iQ-R series SIL2 Process CPU R16PSFCPU Firmwarecisa_csaf_ot

    Customers using the affected products and versions may take measures through mitigations and workarounds. Mitsubishi Electric has released the fixed version as shown above, but updating the product to the fixed version is not available. Mitsubishi Electric recommends users take the following mitigation measures to minimize risk associated with this vulnerability:

  • MitigationMELSEC iQ-R series SIL2 Process CPU R32PSFCPU Firmwarecisa_csaf_ot

    Customers using the affected products and versions may take measures through mitigations and workarounds. Mitsubishi Electric has released the fixed version as shown above, but updating the product to the fixed version is not available. Mitsubishi Electric recommends users take the following mitigation measures to minimize risk associated with this vulnerability:

  • MitigationMELSEC iQ-R series Safety CPU R08SFCPU Firmwarecisa_csaf_ot

    Customers using the affected products and versions may take measures through mitigations and workarounds. Mitsubishi Electric has released the fixed version as shown above, but updating the product to the fixed version is not available. Mitsubishi Electric recommends users take the following mitigation measures to minimize risk associated with this vulnerability:

  • MitigationMELSEC iQ-R series Safety CPU R120SFCPU Firmwarecisa_csaf_ot

    Customers using the affected products and versions may take measures through mitigations and workarounds. Mitsubishi Electric has released the fixed version as shown above, but updating the product to the fixed version is not available. Mitsubishi Electric recommends users take the following mitigation measures to minimize risk associated with this vulnerability:

  • MitigationMELSEC iQ-R series Safety CPU R16SFCPU Firmwarecisa_csaf_ot

    Customers using the affected products and versions may take measures through mitigations and workarounds. Mitsubishi Electric has released the fixed version as shown above, but updating the product to the fixed version is not available. Mitsubishi Electric recommends users take the following mitigation measures to minimize risk associated with this vulnerability:

  • MitigationMELSEC iQ-R series Safety CPU R32SFCPU Firmwarecisa_csaf_ot

    Customers using the affected products and versions may take measures through mitigations and workarounds. Mitsubishi Electric has released the fixed version as shown above, but updating the product to the fixed version is not available. Mitsubishi Electric recommends users take the following mitigation measures to minimize risk associated with this vulnerability:

02

cvss

Technical severity, 0–10. One row per scoring source.

9.1
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 5–9.1

v2.05mediumAV:N/AC:L/Au:N/C:P/I:N/A:Nprimary · NVD / NIST USexploitability 10 · impact 2.9
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Nprimary · NVD / NIST USexploitability 3.9 · impact 3.6
v3.19.1criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Nsecondary · CISA US
v3.17.3highAV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:Lsecondary · FSTEC (BDU) RU
v3.19.1criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Nsecondary · ENISA EU
v3.19.1criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Nsecondary · Mitsubishielectric.Psirt@yd.MitsubishiElectric.co.jpexploitability 3.9 · impact 5.2
v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:Usecondary · CVSS-BT (t0sche)
03

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: totalcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-319USCWE-319USCWE-319USCWE-639US
05

affected products (40)

Products and version ranges known to be affected.

showing 20 of 40
06

advisories (1)

Vendor and ecosystem advisories describing this.

  • ICSA-21-287-03Mitsubishi Electric MELSEC iQ-R Series2021-08-06icsa · cisa_csaf_otUS

    Successful exploitation of this vulnerability could allow a remote attacker to be able to log in to the CPU module by obtaining credentials.

07

also known as (5)

Other names and identifiers for this entity.

08

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bducisa_csaf_otNVDCVE.orgMITRE
published 2021-10-14modified 2026-06-17
09

references (13)

External citations — patches, advisories, analysis.

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