How severe is CVE-2020-5544?

CVE-2020-5544 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-5544 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-5544?

CVE-2020-5544 affects Mitsubishielectric Iu1-1m20-d Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-5544?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-5544 published?

CVE-2020-5544 was published on 2020-03-16 and last updated on 2026-06-17.

CVE-2020-5544

CVE-2020-5544 is a critical-severity vulnerability in Mitsubishielectric Iu1-1m20-d Firmware with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (82nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Mitsubishielectric Iu1-1m20-d Firmware
Published: 2020-03-16
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2020-5544?: 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.
How severe is CVE-2020-5544?: CVE-2020-5544 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-5544 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-5544?: CVE-2020-5544 affects Mitsubishielectric Iu1-1m20-d Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-5544?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-5544 published?: CVE-2020-5544 was published on 2020-03-16 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:mitsubishielectric:iu1-1m20-d_firmware:*:*:*:*:*:*:*:*

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