How severe is CVE-2020-5542?

CVE-2020-5542 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-2020-5542 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-5542?

CVE-2020-5542 affects Mitsubishielectric Iu1-1m20-d Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-5542?

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-2020-5542 published?

CVE-2020-5542 was published on 2020-03-16 and last updated on 2026-06-17.

CVE-2020-5542

CVE-2020-5542 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-119.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-119
Affected product: Mitsubishielectric Iu1-1m20-d Firmware
Published: 2020-03-16
Last modified: 2026-06-17

Description

Buffer error 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-2020-5542?: Buffer error 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-2020-5542?: CVE-2020-5542 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-2020-5542 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-5542?: CVE-2020-5542 affects Mitsubishielectric Iu1-1m20-d Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-5542?: 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-2020-5542 published?: CVE-2020-5542 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:*:*:*:*:*:*:*:*

More vulnerabilities in Mitsubishielectric Iu1-1m20-d Firmware

CVE-2020-16226 — Critical (CVSS 9.8): Multiple Mitsubishi Electric products are vulnerable to impersonations of a legitimate device by a malicious actor,…
CVE-2020-5547 — Critical (CVSS 9.8): Resource Management Errors vulnerability in TCP function included in the firmware of Mitsubishi Electric MELQIC IU1…
CVE-2020-5545 — Critical (CVSS 9.8): TCP function included in the firmware of Mitsubishi Electric MELQIC IU1 series IU1-1M20-D firmware version 1.0.7 and…
CVE-2020-5544 — Critical (CVSS 9.8): Null Pointer Dereference vulnerability in TCP function included in the firmware of Mitsubishi Electric MELQIC IU1…
CVE-2020-5543 — Critical (CVSS 9.8): TCP function included in the firmware of Mitsubishi Electric MELQIC IU1 series IU1-1M20-D firmware version 1.0.7 and…
CVE-2020-5546 — High (CVSS 8.8): Improper Neutralization of Argument Delimiters in a Command ('Argument Injection') vulnerability in TCP function…

All CVEs affecting Mitsubishielectric Iu1-1m20-d Firmware →

Other CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) vulnerabilities

CVE-2026-2778 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability was fixed in…
CVE-2026-2776 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software. This vulnerability…
CVE-2025-1866 — Critical (CVSS 10.0): Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in warmcat libwebsockets allows…
CVE-2022-27625 — Critical (CVSS 10.0): A vulnerability regarding improper restriction of operations within the bounds of a memory buffer is found in the…
CVE-2022-27624 — Critical (CVSS 10.0): A vulnerability regarding improper restriction of operations within the bounds of a memory buffer is found in the…
CVE-2020-11896 — Critical (CVSS 10.0): The Treck TCP/IP stack before 6.0.1.66 allows Remote Code Execution, related to IPv4 tunneling.

Browse all CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) vulnerabilities →