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CVE Record

CVE-2021-20597: Insufficiently Protected Credentials vulnerability in Mitsubishi Electric MELSEC iQ-R series Safety CPU mod...

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.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This flaw can expose login credentials for specific Mitsubishi Electric MELSEC iQ-R safety and SIL2 process CPU modules when user information is registered or passwords are changed. An attacker able to sniff that network traffic could use the captured credentials to log in without authorization.

Executive priority

Prioritize review where these CPUs support safety or process operations. The issue is not reported as actively exploited here, but unauthorized access to OT control assets can carry operational and safety consequences.

Technical view

CVE-2021-20597 is an insufficiently protected credentials issue affecting listed MELSEC iQ-R R08/16/32/120SFCPU firmware version 26 and prior, and R08/16/32/120PSFCPU firmware version 11 and prior. The described attack requires observing network traffic during user registration or password change, then reusing obtained credentials.

Likely exposure

Exposure is most likely in OT environments using the affected Mitsubishi safety or SIL2 process CPU modules where management traffic is reachable to other network hosts. Internet exposure is not stated in the provided sources.

Exploitation context

The source bundle does not show KEV listing or active exploitation. The described path requires network sniffing during specific credential-management actions, which limits opportunity but is serious in safety or process-control environments.

Researcher notes

Evidence is limited to the CVE description and listed advisories. No CVSS vector, CWE, exploit publication, or KEV status is provided in the bundle. Avoid assuming exploitability beyond credential capture during registration or password-change traffic.

Mitigation direction

  • Check Mitsubishi Electric and CISA guidance for vendor-approved firmware or mitigations.
  • Inventory affected MELSEC iQ-R Safety CPU and SIL2 Process CPU firmware versions.
  • Restrict management access to trusted OT administration networks only.
  • Avoid credential changes over networks where untrusted hosts can observe traffic.
  • Rotate credentials after applying vendor-approved remediation or compensating controls.

Validation and detection

  • Identify deployed R08/16/32/120SFCPU and R08/16/32/120PSFCPU modules.
  • Compare firmware against version 26 and prior, or version 11 and prior respectively.
  • Review whether user registration or password changes traverse shared or monitorable networks.
  • Check logs for unexpected logins after recent credential-management activity.
  • Confirm remediation status against Mitsubishi Electric or CISA advisory details.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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description · low confidence lookup

Credential and access behavior lookup

The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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cve · low confidence lookup

CVE-2021-20597 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
4Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/aMitsubishi Electric MELSEC iQ-R series Safety CPU modules R08/16/32/120SFCPU; Mitsubishi Electric MELSEC iQ-R series SIL2 Process CPU modules R08/16/32/120PSFCPUMitsubishi Electric MELSEC iQ-R series Safety CPU modules R08/16/32/120SFCPU firmware versions "26" and prior, Mitsubishi Electric MELSEC iQ-R series SIL2 Process CPU modules R08/16/32/120PSFCPU firmware versions "11" and priorunaffected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.