HOMEVULNERABILITIESCVE-2021-20600
MEDIUM

CVE-2021-20600

CWE-400Published: October 8, 2021· Updated: Jun 17, 2026

5.9
CVSS v3.1

Official Description

Uncontrolled resource consumption in Mitsubishi Electric MELSEC iQ-R series C Controller Module R12CCPU-V Firmware Versions "16" and prior allows a remote unauthenticated attacker to cause a denial-of-service (DoS) condition by sending a large number of packets in a short time while the module starting up. System reset is required for recovery.

NVD Source

Technical Analysis

CVE-2021-20600 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 5.9.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityHigh
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Vendors & Products

mitsubishielectric2 product(s)
r12ccpu-v firmwarer12ccpu-v
Source: NVD CPE · 2 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://jvn.jp/vu/JVNVU94914666/index.html
ADVISORYhttps://us-cert.cisa.gov/ics/advisories/icsa-21-280-04
ADVISORYhttps://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-015_en.pdf
ADVISORYhttps://jvn.jp/vu/JVNVU94914666/index.html
ADVISORYhttps://us-cert.cisa.gov/ics/advisories/icsa-21-280-04
ADVISORYhttps://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-015_en.pdf

All References (6)

→
https://jvn.jp/vu/JVNVU94914666/index.htmlThird Party Advisory
→
https://us-cert.cisa.gov/ics/advisories/icsa-21-280-04Third Party Advisory · US Government Resource
→
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-015_en.pdfVendor Advisory
→
https://jvn.jp/vu/JVNVU94914666/index.htmlThird Party Advisory
→
https://us-cert.cisa.gov/ics/advisories/icsa-21-280-04Third Party Advisory · US Government Resource
→
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-015_en.pdfVendor Advisory

Quick Facts

CVE IDCVE-2021-20600
CVSS Score5.9 / 10
SeverityMEDIUM
WeaknessCWE-400
CISA KEVNo
Affected1 vendor(s)
PublishedOct 8, 2021

Related CVEs (CWE-400)

CVE-2024-45166
9.8
CVE-2017-1000378
9.8
CVE-2024-39462
9.8
CVE-2013-20004
9.8
CVE-2025-43193
9.8
CVE-2015-4412
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-20600 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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