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CRITICAL

CVE-2021-20599

CVE-2021-20599 Vulnerability Analysis & Exploit Intelligence

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.

Published Updated Sources: cvelistV5, Mitsubishi

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

1%

chance of exploitation in 30 days

Affects

mitsubishi electric

16 products listed

CVSS base

9.1

CRITICAL

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

None

none · proof-of-concept · active

Automatable

Yes

can an attacker script all four kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Affected scope

The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.

Products (16)

melsec iq r series safety cpu r08sfcpumelsec iq r series safety cpu r16sfcpumelsec iq r series safety cpu r32sfcpumelsec iq r series safety cpu r120sfcpumelsec iq r series sil2 process cpu r08psfcpumelsec iq r series sil2 process cpu r16psfcpumelsec iq r series sil2 process cpu r32psfcpumelsec iq r series sil2 process cpu r120psfcpumelsec iq r08sfcpur16sfcpur32sfcpur120sfcpur08psfcpur16psfcpur32psfcpur120psfcpu

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactSource
9.1CVSS 3.1CRITICAL——cvelistV5

Weakness & attack patterns

  • CWE-319

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

  • T1056.004Input Capture: Credential API Hooking
  • T1040Network Sniffing

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

  • Search application, proxy, and WAF logs for requests touching /16/32/120SFCPU, /16/32/120PSFCPU.

References

3 on the record

Elsewhere on this site

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.