HOMEVULNERABILITIESCVE-2020-5665
HIGH

CVE-2020-5665

NVD-CWE-noinfoPublished: December 14, 2020· Updated: Jun 17, 2026

7.4
CVSS v3.1

Official Description

Improper check or handling of exceptional conditions in MELSEC iQ-F series FX5U(C) CPU unit firmware version 1.060 and earlier allows an attacker to cause a denial-of-service (DoS) condition on program execution and communication by sending a specially crafted ARP packet.

NVD Source

Technical Analysis

CVE-2020-5665 requires adjacent network access, limiting remote exploitation but still posing risk in shared or local network environments.

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 7.4.

The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorAdjacent
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeChanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Affected Vendors & Products

mitsubishielectric2 product(s)
melsec iq-f fx5u cpu firmwaremelsec iq-f fx5u cpu
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/JVNVU95638588/index.html
ADVISORYhttps://us-cert.cisa.gov/ics/advisories/icsa-20-345-01
ADVISORYhttps://www.mitsubishielectric.co.jp/psirt/vulnerability/pdf/2020-018.pdf
ADVISORYhttps://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2020-018_en.pdf
ADVISORYhttps://jvn.jp/vu/JVNVU95638588/index.html
ADVISORYhttps://us-cert.cisa.gov/ics/advisories/icsa-20-345-01
ADVISORYhttps://www.mitsubishielectric.co.jp/psirt/vulnerability/pdf/2020-018.pdf
ADVISORYhttps://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2020-018_en.pdf

All References (8)

→
https://jvn.jp/vu/JVNVU95638588/index.htmlThird Party Advisory
→
https://us-cert.cisa.gov/ics/advisories/icsa-20-345-01Third Party Advisory · US Government Resource
→
https://www.mitsubishielectric.co.jp/psirt/vulnerability/pdf/2020-018.pdfVendor Advisory
→
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2020-018_en.pdfVendor Advisory
→
https://jvn.jp/vu/JVNVU95638588/index.htmlThird Party Advisory
→
https://us-cert.cisa.gov/ics/advisories/icsa-20-345-01Third Party Advisory · US Government Resource
→
https://www.mitsubishielectric.co.jp/psirt/vulnerability/pdf/2020-018.pdfVendor Advisory
→
https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2020-018_en.pdfVendor Advisory

Quick Facts

CVE IDCVE-2020-5665
CVSS Score7.4 / 10
SeverityHIGH
WeaknessNVD-CWE-noinfo
CISA KEVNo
Affected1 vendor(s)
PublishedDec 14, 2020

Related CVEs (NVD-CWE-noinfo)

CVE-2023-45894
10.0
CVE-2024-22216
10.0
CVE-2019-25136
10.0
CVE-2023-40455
10.0
CVE-2023-38586
10.0
CVE-2008-4873
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2020-5665 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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