Uncontrolled resource consumption in Mitsubishi Electric MELSEC iQ-R series C Controller Module R12CCPU-V Firmware Versions "16" and prior…

published 2021-10-08 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-8018

cvss: 5.9; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 2.4%; EPSS 2.4% chance of exploitation in 30 days, percentile 84%
public exploits: 0; none known

Uncontrolled resource consumption in Mitsubishi Electric MELSEC iQ-R series C Controller Module R12CCPU-V Firmware Versions "16" and prior allows a remote unauthenticated attacker to cause a denial-of-service (DoS) condition by sending a large number of packets in a short time while the module starting up. System reset is required for recovery.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-21-280-04 updated 2021-10-28 cvss 6.8

Mitsubishi Electric MELSEC iQ-R Series C Controller Module (Update B)

Mitsubishi Electric R12CCPU-V <= 16
affected: mitigation “Mitsubishi Electric recommends users update affected devices to Firmware Version 17 or later. For specific update instructions and additional details see the Mitsubishi Electric advisory.” mitsubishielectric.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

Exploit prediction

2.38% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	5.9	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD	2.0	7.1	AV:N/AC:M/Au:N/C:N/I:N/A:C

Affected products

n/a Mitsubishi Electric MELSEC iQ-R series C Controller Module R12CCPU-V

Classification

Weakness

CWE-400 Uncontrolled Resource Consumption

References

mitsubishielectric.com /en/psirt/vulnerability/pdf/2021-015_en.pdf
vendor-advisory
jvn.jp /vu/JVNVU94914666/index.html
third-party-advisory
us-cert.cisa.gov /ics/advisories/icsa-21-280-04
third-party-advisory, us-government-resource

Sources

CVE List CVE-2021-20600
NVD CVE-2021-20600

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary