R00Cpu Firmware
CVE-2021-20591
HIGH
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V2 - Validation and Business Logic Resource consumption limits
MITRE ATT&CK
1 technique across 1 tactic: Impact The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. |
| Exploit ScenarioDerived | A remote attacker could cause denial of service by exhausting system resources by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability. |
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Alert meAnalysisAI
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. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Implement rate limiting, set resource quotas, validate input sizes, use timeouts.
Affects your stack
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Technical ContextAI · show details
This vulnerability is classified as Uncontrolled Resource Consumption (CWE-400), which allows attackers to cause denial of service by exhausting system resources. 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. Affected products include: Mitsubishielectric R00Cpu Firmware, Mitsubishielectric R01Cpu Firmware, Mitsubishielectric R02Cpu Firmware, Mitsubishielectric R04Cpu Firmware, Mitsubishielectric R08Cpu Firmware.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
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.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Affected Products (CPE)NVD
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NVD
CVE.org
EPSS
GitHub PoC
Exploit-DB