CVE-2021-20591
Uncontrolled Resource Consumption vulnerability in Mitsubishi Electric MELSEC iQ-R series CPU...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2021-20591- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 7.8 High
AV:N/AC:L/Au:N/C:N/I:N/A:C - Weakness
- CWE-400
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2021-20591- Updated
- 2026-11-02
EUVDEUVD-2021-8009 No score
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.
- Record
EUVD-2021-8009- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-mhpv-hfp2-2648 No score
Uncontrolled Resource Consumption vulnerability in Mitsubishi Electric MELSEC iQ-R series CPU...
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.
- Record
GHSA-mhpv-hfp2-2648- Weakness
- CWE-400
- Updated
- 2026-11-02
Affected products
- mitsubishi electric corporation melsec iq-r series cpu modules
- mitsubishielectric r00cpu firmware
- mitsubishielectric r01cpu firmware
- mitsubishielectric r02cpu firmware
- mitsubishielectric r04cpu firmware
- mitsubishielectric r08cpu firmware
- mitsubishielectric r08pcpu firmware
- mitsubishielectric r08psfcpu firmware
- mitsubishielectric r08sfcpu firmware
- mitsubishielectric r120cpu firmware
- mitsubishielectric r120pcpu firmware
- mitsubishielectric r120psfcpu firmware
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- mitsubishielectric r120sfcpu firmware
- mitsubishielectric r16cpu firmware
- mitsubishielectric r16pcpu firmware
- mitsubishielectric r16psfcpu firmware
- mitsubishielectric r16sfcpu firmware
- mitsubishielectric r32cpu firmware
- mitsubishielectric r32pcpu firmware
- mitsubishielectric r32psfcpu firmware
- mitsubishielectric r32sfcpu firmware
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | ||
| aliases, products | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-20591 is a high vulnerability (CVSS 7.5) in Mitsubishi Electric Corporation Melsec Iq-r Series Cpu Modules, published June 11, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.50%, the 74th percentile. No source names a fixed version.