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Full vulnerability report · 2021
CVE-2021-20610High confidence

Mitsubishi Electric Corporation MELSEC iQ-R Series R00CPU — Improper Handling of Length Parameter Inconsistency

Mitsubishi Electric Corporation · MELSEC iQ-R Series R00CPU

7.5HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 3.27% for the current model date.

Compensating controls

  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Mitsubishi Electric Corporation MELSEC iQ-R Series R00CPU and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 30 daysRemediation target: Within 180 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2021-8028

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified
01

What, why and how

Improper Handling of Length Parameter Inconsistency vulnerability in Mitsubishi Electric MELSEC iQ-R Series R00/01/02CPU, MELSEC iQ-R Series R04/08/16/32/120(EN)CPU, MELSEC iQ-R Series R08/16/32/120SFCPU, MELSEC iQ-R Series R08/16/32/120PCPU, MELSEC iQ-R Series R08/16/32/120PSFCPU, MELSEC iQ-R Series R16/32/64MTCPU, MELSEC iQ-R Series R12CCPU-V, MELSEC Q Series Q03UDECPU, MELSEC Q Series Q04/06/10/13/20/26/50/100UDEHCPU, MELSEC Q Series Q03/04/06/13/26UDVCPU, MELSEC Q Series Q04/06/13/26UDPVCPU, MELSEC Q Series Q12DCCPU-V, MELSEC Q Series Q24DHCCPU-V(G), MELSEC Q Series Q24/26DHCCPU-LS, MELSEC Q Series MR-MQ100, MELSEC Q Series Q172/173DCPU-S1, MELSEC Q Series Q172/173DSCPU, MELSEC Q Series Q170MCPU, MELSEC Q Series Q170MSCPU(-S1), MELSEC L Series L02/06/26CPU(-P), MELSEC L Series L26CPU-(P)BT and MELIPC Series MI5122-VW allows a remote unauthenticated attacker to cause a denial-of-service (DoS) condition by sending specially crafted packets. System reset is required for recovery.

What

Improper Handling of Length Parameter Inconsistency vulnerability in Mitsubishi Electric MELSEC iQ-R Series R00/01/02CPU, MELSEC iQ-R Series R04/08/16/32/120(EN)CPU, MELSEC iQ-R Series R08/16/32/120SFCPU, MELSEC iQ-R Series R08/16/32/120PCPU, MELSEC iQ-R Series R08/16/32/120PSFCPU, MELSEC iQ-R Series R16/32/64MTCPU, MELSEC iQ-R Series R12CCPU-V, MELSEC Q Series Q03UDECPU, MELSEC Q Series Q04/06/10/13/20/26/50/100UDEHCPU, MELSEC Q Series Q03/04/06/13/26UDVCPU, MELSEC Q Series Q04/06/13/26UDPVCPU, MELSEC Q Series Q12DCCPU-V, MELSEC Q Series Q24DHCCPU-V(G), MELSEC Q Series Q24/26DHCCPU-LS, MELSEC Q Series MR-MQ100, MELSEC Q Series Q172/173DCPU-S1, MELSEC Q Series Q172/173DSCPU, MELSEC Q Series Q170MCPU, MELSEC Q Series Q170MSCPU(-S1), MELSEC L Series L02/06/26CPU(-P), MELSEC L Series L26CPU-(P)BT and MELIPC Series MI5122-VW allows a remote unauthenticated attacker to cause a denial-of-service (DoS) condition by sending specially crafted packets. System reset is required for recovery.

Why

The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Improper Handling of Length Parameter Inconsistency vulnerability in Mitsubishi Electric MELSEC iQ-R Series R00/01/02CPU, MELSEC iQ-R Series R04/08/16/32/120(EN)CPU, MELSEC iQ-R Series R08/16/32/120SFCPU, MELSEC iQ-R Series R08/16/32/120PCPU, MELSEC iQ-R Series R08/16/32/120PSFCPU, MELSEC iQ-R Series R16/32/64MTCPU, MELSEC iQ-R Series R12CCPU-V, MELSEC Q Series Q03UDECPU, MELSEC Q Series Q04/06/10/13/20/26/50/100UDEHCPU, MELSEC Q Series Q03/04/06/13/26UDVCPU, MELSEC Q Series Q04/06/13/26UDPVCPU, MELSEC Q Series Q12DCCPU-V, MELSEC Q Series Q24DHCCPU-V(G), MELSEC Q Series Q24/26DHCCPU-LS, MELSEC Q Series MR-MQ100, MELSEC Q Series Q172/173DCPU-S1, MELSEC Q Series Q172/173DSCPU, MELSEC Q Series Q170MCPU, MELSEC Q Series Q170MSCPU(-S1), MELSEC L Series L02/06/26CPU(-P), MELSEC L Series L26CPU-(P)BT and MELIPC Series MI5122-VW allows a remote unauthenticated attacker to cause a denial-of-service (DoS) condition by sending specially crafted packets. System reset is required for recovery.

Why

The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Improper Handling of Length Parameter Inconsistency → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-130 ↗

CWE-130: Improper Handling of Length Parameter Inconsistency. The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-130
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

Cyber Security Agency of Singapore · English · CSA-SB-20211208Security Bulletin 08 Dec 2021

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 08 Dec 2021, published on 8 December 2021. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-005273MELSEC および MELIPC シリーズにおける脆弱性

MELSEC および MELIPC シリーズには、不特定の脆弱性が存在します。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix not verified
Affected
  • MELSEC iQ-R Series R00CPU: Firmware versions "24" and prior
  • MELSEC iQ-R Series R01CPU: Firmware versions "24" and prior
  • MELSEC iQ-R Series R02CPU: Firmware versions "24" and prior
  • MELSEC iQ-R Series R04CPU: Firmware versions "57" and prior
  • MELSEC iQ-R Series R08CPU: Firmware versions "57" and prior
  • MELSEC iQ-R Series R16CPU: Firmware versions "57" and prior
  • MELSEC iQ-R Series R32CPU: Firmware versions "57" and prior
  • MELSEC iQ-R Series R120CPU: Firmware versions "57" and prior
  • MELSEC iQ-R Series R04ENCPU: Firmware versions "57" and prior
  • MELSEC iQ-R Series R08ENCPU: Firmware versions "57" and prior
  • MELSEC iQ-R Series R16ENCPU: Firmware versions "57" and prior
  • MELSEC iQ-R Series R32ENCPU: Firmware versions "57" and prior
  • MELSEC iQ-R Series R120ENCPU: Firmware versions "57" and prior
  • MELSEC iQ-R Series R08SFCPU: Firmware versions "26" and prior
  • MELSEC iQ-R Series R16SFCPU: Firmware versions "26" and prior
  • MELSEC iQ-R Series R32SFCPU: Firmware versions "26" and prior
  • MELSEC iQ-R Series R120SFCPU: Firmware versions "26" and prior
  • MELSEC iQ-R Series R08PCPU: Firmware versions "29" and prior
  • MELSEC iQ-R Series R16PCPU: Firmware versions "29" and prior
  • MELSEC iQ-R Series R32PCPU: Firmware versions "29" and prior
  • MELSEC iQ-R Series R120PCPU: Firmware versions "29" and prior
  • MELSEC iQ-R Series R08PSFCPU: Firmware versions "08" and prior
  • MELSEC iQ-R Series R16PSFCPU: Firmware versions "08" and prior
  • MELSEC iQ-R Series R32PSFCPU: Firmware versions "08" and prior
  • MELSEC iQ-R Series R120PSFCPU: Firmware versions "08" and prior
  • MELSEC iQ-R Series R16MTCPU: Operating system software version "23" and prior
  • MELSEC iQ-R Series R32MTCPU: Operating system software version "23" and prior
  • MELSEC iQ-R Series R64MTCPU: Operating system software version "23" and prior
  • MELSEC iQ-R Series R12CCPU-V: Firmware versions "16" and prior
  • MELSEC Q Series Q03UDECPU: The first 5 digits of serial No. "23121" and prior
  • MELSEC Q Series Q04UDEHCPU: The first 5 digits of serial No. "23121" and prior
  • MELSEC Q Series Q06UDEHCPU: The first 5 digits of serial No. "23121" and prior
  • MELSEC Q Series Q10UDEHCPU: The first 5 digits of serial No. "23121" and prior
  • MELSEC Q Series Q13UDEHCPU: The first 5 digits of serial No. "23121" and prior
  • MELSEC Q Series Q20UDEHCPU: The first 5 digits of serial No. "23121" and prior
  • MELSEC Q Series Q26UDEHCPU: The first 5 digits of serial No. "23121" and prior
  • MELSEC Q Series Q50UDEHCPU: The first 5 digits of serial No. "23121" and prior
  • MELSEC Q Series Q100UDEHCPU: The first 5 digits of serial No. "23121" and prior
  • MELSEC Q Series Q03UDVCPU: The first 5 digits of serial No. "23071" and prior
  • MELSEC Q Series Q04UDVCPU: The first 5 digits of serial No. "23071" and prior
  • MELSEC Q Series Q06UDVCPU: The first 5 digits of serial No. "23071" and prior
  • MELSEC Q Series Q13UDVCPU: The first 5 digits of serial No. "23071" and prior
  • MELSEC Q Series Q26UDVCPU: The first 5 digits of serial No. "23071" and prior
  • MELSEC Q Series Q04UDPVCPU: The first 5 digits of serial No. "23071" and prior
  • MELSEC Q Series Q06UDPVCPU: The first 5 digits of serial No. "23071" and prior
  • MELSEC Q Series Q13UDPVCPU: The first 5 digits of serial No. "23071" and prior
  • MELSEC Q Series Q26UDPVCPU: The first 5 digits of serial No. "23071" and prior
  • MELSEC Q Series Q12DCCPU-V: The first 5 digits of serial No. "24031" and prior
  • MELSEC Q Series Q24DHCCPU-V: The first 5 digits of serial No. "24031" and prior
  • MELSEC Q Series Q24DHCCPU-VG: The first 5 digits of serial No. "24031" and prior
  • MELSEC Q Series Q24DHCCPU-LS: The first 5 digits of serial No. "24031" and prior
  • MELSEC Q Series Q26DHCCPU-LS: The first 5 digits of serial No. "24031" and prior
  • MELSEC Q Series MR-MQ100: Operating system software version "F" and prior
  • MELSEC Q Series Q172DCPU-S1: Operating system software version "W" and prior
  • MELSEC Q Series Q173DCPU-S1: Operating system software version "W" and prior
  • 14 additional product groups retained in the authoritative source
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 1 Dec 2021 · Last source change 3 Aug 2024, 17:45 UTC · CWE-130 · Improper Handling of Length Parameter Inconsistency

CVE recordCVE.org · 5.1
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2021-8028
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2021-8028↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2021-20610 · cve.blacktree.nl