CVE-2020-5656

9.8 CRITICAL 3% exploit odds Fix listed Other Device

What it is

Improper access control vulnerability in TCP/IP function included in the firmware of MELSEC iQ-R series (RJ71EIP91 EtherNet/IP Network Interface Module First 2 digits of serial number are '02' or before, RJ71PN92 PROFINET IO Controller Module First 2 digits of serial number are '01' or before, RD81DL96 High Speed Data Logger Module First 2 digits of serial number are '08' or before, RD81MES96N MES Interface Module First 2 digits of serial number are '04' or before, and RD81OPC96 OPC UA Server Module First 2 digits of serial number are '04' or before) allows a remote unauthenticated attacker to stop the network functions of the products or execute a malicious program via a specially crafted packet.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
Exploit odds: 3.0% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2020-11-02 21:15 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: 3.0% in the next 30 days (EPSS).
Severity: 9.8 CRITICAL (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2020-11-02 21:15 UTC
Last modified: 2026-06-17 03:22 UTC
Exploit probability: 3.0% · EPSS, next 30 days
Record status: Modified

Affected

Mitsubishielectric Melsec iq-rj71eip91 Firmware
Mitsubishielectric Melsec iq-rj71pn92 Firmware
Mitsubishielectric Melsec iq-rd81dl96 Firmware
Mitsubishielectric Melsec iq-rd81mes96n Firmware
Mitsubishielectric Melsec iq-rd81opc96 Firmware

Attack profile CVSS 3.1 · 9.8

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

Raw vector

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

Is it in your code?

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Fix and advisories

References

NVD record · CVE.org record