CVE-2020-5666

7.5 HIGH 9% exploit odds Fix listed Denial of service Device

What it is

Uncontrolled resource consumption vulnerability in MELSEC iQ-R Series CPU Modules (R00/01/02CPU Firmware versions from '05' to '19' and R04/08/16/32/120(EN)CPU Firmware versions from '35' to '51') allows a remote attacker to cause an error in a CPU unit via a specially crafted HTTP packet, which may lead to a denial-of-service (DoS) condition in execution of the program and its communication.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of service disruption.
Exploit odds: 8.8% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2020-11-16 01:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 03:22 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 8.8% in the next 30 days (EPSS).
Severity: 7.5 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2020-11-16 01:15 UTC
Last modified: 2026-06-17 03:22 UTC
Exploit probability: 8.8% · EPSS, next 30 days
Weakness: CWE-400 · Uncontrolled resource consumption
Record status: Modified

Affected

Mitsubishielectric Melsec iq-r00 Firmware ≤ 19
Mitsubishielectric Melsec iq-r01 Firmware ≤ 19
Mitsubishielectric Melsec iq-r02 Firmware ≤ 19
Mitsubishielectric Melsec iq-r04 Firmware ≤ 51
Mitsubishielectric Melsec iq-r16 Firmware ≤ 51
Mitsubishielectric Melsec iq-r08 Firmware ≤ 51
Mitsubishielectric Melsec iq-r32 Firmware ≤ 51
Mitsubishielectric Melsec iq-r120 Firmware ≤ 51

Attack profile CVSS 3.1 · 7.5

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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Fix and advisories

References

NVD record · CVE.org record