HOMEVULNERABILITIESCVE-2020-5544
CRITICAL

CVE-2020-5544

CWE-476Published: March 16, 2020· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official Description

Null Pointer Dereference vulnerability in TCP function included in the firmware of Mitsubishi Electric MELQIC IU1 series IU1-1M20-D firmware version 1.0.7 and earlier allows remote attackers to stop the network functions or execute malware via a specially crafted packet.

NVD Source

Technical Analysis

CVE-2020-5544 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 complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

mitsubishielectric2 product(s)
iu1-1m20-d firmwareiu1-1m20-d
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

PATCHhttps://www.mitsubishielectric.co.jp/psirt/vulnerability/pdf/2019-004.pdf
PATCHhttps://www.mitsubishielectric.co.jp/psirt/vulnerability/pdf/2019-004.pdf
ADVISORYhttps://jvn.jp/en/vu/JVNVU92370624/index.html
ADVISORYhttps://jvn.jp/en/vu/JVNVU92370624/index.html

All References (4)

→
https://jvn.jp/en/vu/JVNVU92370624/index.htmlThird Party Advisory
→
https://www.mitsubishielectric.co.jp/psirt/vulnerability/pdf/2019-004.pdfPatch · Vendor Advisory
→
https://jvn.jp/en/vu/JVNVU92370624/index.htmlThird Party Advisory
→
https://www.mitsubishielectric.co.jp/psirt/vulnerability/pdf/2019-004.pdfPatch · Vendor Advisory

Quick Facts

CVE IDCVE-2020-5544
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-476
CISA KEVNo
Affected1 vendor(s)
PublishedMar 16, 2020

Related CVEs (CWE-476)

CVE-2010-2495
10.0
CVE-2022-36648
10.0
CVE-2015-8787
9.8
CVE-2015-9073
9.8
CVE-2015-9043
9.8
CVE-2016-10344
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2020-5544 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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