CVE-2020-5668

What it is

Uncontrolled resource consumption vulnerability in MELSEC iQ-R Series modules (R00/01/02CPU firmware version '19' and earlier, R04/08/16/32/120 (EN) CPU firmware version '51' and earlier, R08/16/32/120SFCPU firmware version '22' and earlier, R08/16/32/120PCPU firmware version '25' and earlier, R08/16/32/120PSFCPU firmware version '06' and earlier, RJ71EN71 firmware version '47' and earlier, RJ71GF11-T2 firmware version '47' and earlier, RJ72GF15-T2 firmware version '07' and earlier, RJ71GP21-SX firmware version '47' and earlier, RJ71GP21S-SX firmware version '47' and earlier, and RJ71GN11-T2 firmware version '11' and earlier) allows a remote unauthenticated attacker to cause an error in a CPU unit and cause a denial-of-service (DoS) condition in execution of the program and its communication, or to cause a denial-of-service (DoS) condition in communication via the unit by receiving a specially crafted SLMP packet

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

4.9% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2020-11-20 04:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 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: 4.9% in the next 30 days (EPSS).
• Severity: 7.5 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2020-11-20 04:15 UTC

Last modified

2026-06-17 03:22 UTC

Exploit probability

4.9% · EPSS, next 30 days

Weakness

CWE-400 · Uncontrolled resource consumption

Record status

Modified

Affected

• Mitsubishielectric r00cpu Firmware ≤ 19
• Mitsubishielectric r01cpu Firmware ≤ 19
• Mitsubishielectric r02cpu Firmware ≤ 19
• Mitsubishielectric r04cpu Firmware ≤ 51
• Mitsubishielectric r08cpu Firmware ≤ 51
• Mitsubishielectric r16cpu Firmware ≤ 51
• Mitsubishielectric r32cpu Firmware ≤ 51
• Mitsubishielectric r120cpu 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

Is it in your code?

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