TI-2021-03824 Aliases CVE-2021-20591 GHSA-mhpv-hfp2-2648

Uncontrolled resource consumption in MELSEC iQ-R series CPU modules

LOW 36CWE-400Published 2021-06-11 · Updated 2024-08-03

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-400.

Summary

Uncontrolled Resource Consumption vulnerability in Mitsubishi Electric MELSEC iQ-R series CPU modules (R00/01/02CPU all versions, R04/08/16/32/120(EN)CPU all versions, R08/16/32/120SFCPU all versions, R08/16/32/120PCPU all versions, R08/16/32/120PSFCPU all versions) allows a remote unauthenticated attacker to prevent legitimate clients from connecting to the MELSOFT transmission port (TCP/IP) by not closing a connection properly, which may lead to a denial of service (DoS) condition.

Why it matters now

EPSS 0.01497 74th percentileScored 2026-11-07

Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
—	MELSEC iQ-R series CPU modules	R00/01/02CPU all versions, R04/08/16/32/120(EN)CPU all versions, R08/16/32/120SFCPU all versions, R08/16/32/120PCPU all versions, R08/16/32/120PSFCPU all versions	—	No fix listed	CNA

MELSEC iQ-R series CPU modules Vendor— Affected R00/01/02CPU all versions, R04/08/16/32/120(EN)CPU all versions, R08/16/32/120SFCPU all versions, R08/16/32/120PCPU all versions, R08/16/32/120PSFCPU all versions Fixed in — No fix listed CNA

CPE configurations NVD · 40

CPE	Versions	Role	Vendor
cpe:2.3:o:mitsubishielectric:r00cpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r00cpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r01cpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r01cpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r02cpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r02cpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r04cpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r04cpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r08cpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r08cpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.

cpe:2.3:o:mitsubishielectric:r00cpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r00cpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r01cpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r01cpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r02cpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r02cpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r04cpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r04cpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r08cpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r08cpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.

Show 30 more CPE

CPE	Versions	Role	Vendor
cpe:2.3:o:mitsubishielectric:r16cpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r16cpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r32cpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r32cpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r120cpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r120cpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r08sfcpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r08sfcpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r16sfcpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r16sfcpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r32sfcpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r32sfcpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r120sfcpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r120sfcpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r08pcpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r08pcpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r16pcpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r16pcpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r32pcpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r32pcpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r120pcpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r120pcpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r08psfcpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r08psfcpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r16psfcpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r16psfcpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r32psfcpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r32psfcpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r120psfcpu_firmware::::::::	all versions	Vulnerable	Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r120psfcpu:-:::::::*	not specified by NVD	Running on	Mitsubishi Electric Europe B.V.

cpe:2.3:o:mitsubishielectric:r16cpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r16cpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r32cpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r32cpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r120cpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r120cpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r08sfcpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r08sfcpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r16sfcpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r16sfcpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r32sfcpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r32sfcpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r120sfcpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r120sfcpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r08pcpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r08pcpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r16pcpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r16pcpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r32pcpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r32pcpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r120pcpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r120pcpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r08psfcpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r08psfcpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r16psfcpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r16psfcpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r32psfcpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r32psfcpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.
cpe:2.3:o:mitsubishielectric:r120psfcpu_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Mitsubishi Electric Europe B.V.
cpe:2.3:h:mitsubishielectric:r120psfcpu:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Mitsubishi Electric Europe B.V.

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2021-20591
2026-10-03 Alias added: GHSA-mhpv-hfp2-2648

References

Advisory 2

TI-2022-19113 Authentication Bypass Vulnerability in Web Server Function on MELSEC Series CVSS 3.1CRITICAL 9.1
TI-2020-04633 Uncontrolled resource consumption in Mitsubishi Electric Corporation MELSEC iQ-R CVSS 3.1HIGH 7.5
TI-2020-12854 Mitsubishi MELSEC iQ-R Series PLCs with firmware 49 allow an unauthenticated attacker to… CVSS 3.1HIGH 7.5
TI-2020-04497 Uncontrolled resource consumption in Mitsubishi Electric Corporation MELSOFT transmission… CVSS 3.1HIGH 7.5

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences