Incorrect Implementation of Authentication Algorithm in Mitsubishi Electric Air Conditioning System/Centralized Controllers (G-50A Ver.2.50…

published 2021-07-13 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-8011

cvss: 7.1; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.9%; EPSS 0.9% chance of exploitation in 30 days, percentile 58%
public exploits: 0; none known

Incorrect Implementation of Authentication Algorithm in Mitsubishi Electric Air Conditioning System/Centralized Controllers (G-50A Ver.2.50 to Ver. 3.35, GB-50A Ver.2.50 to Ver. 3.35, AG-150A-A Ver.3.20 and prior, AG-150A-J Ver.3.20 and prior, GB-50ADA-A Ver.3.20 and prior, GB-50ADA-J Ver.3.20 and prior, EB-50GU-A Ver 7.09 and prior, EB-50GU-J Ver 7.09 and prior, AE-200A Ver 7.93 and prior, AE-200E Ver 7.93 and prior, AE-50A Ver 7.93 and prior, AE-50E Ver 7.93 and prior, EW-50A Ver 7.93 and prior, EW-50E Ver 7.93 and prior, TE-200A Ver 7.93 and prior, TE-50A Ver 7.93 and prior, TW-50A Ver 7.93 and prior, CMS-RMD-J Ver.1.30 and prior) and Air Conditioning System/Expansion Controllers (PAC-YG50ECA Ver.2.20 and prior) allows a remote authenticated attacker to impersonate administrators to disclose configuration information of the air conditioning system and tamper information (e.g. operation information and configuration of air conditioning system) by exploiting this vulnerability.

Vendor advisories

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

cisa ICSA-21-182-04 updated 2021-07-01 cvss 7.1

Mitsubishi Electric Air Conditioning System

Mitsubishi Electric AE-50A <= 7.93 Mitsubishi Electric AE-50E <= 7.93 Mitsubishi Electric AE-200A <= 7.93 Mitsubishi Electric AE-200E <= 7.93 Mitsubishi Electric AG-150A-A <= 3.20 Mitsubishi Electric AG-150A-J <= 3.20

+13 more productsfewer

Mitsubishi Electric CMS-RMD-J <= 1.30 Mitsubishi Electric EB-50GU-A <= 7.09 Mitsubishi Electric EB-50GU-J <= 7.09 Mitsubishi Electric EW-50A <= 7.93 Mitsubishi Electric EW-50E <= 7.93 Mitsubishi Electric G-50A >= 2.50, <= 3.35 Mitsubishi Electric GB-50A >= 2.50, <= 3.35 Mitsubishi Electric GB-50ADA-A <= 3.20 Mitsubishi Electric GB-50ADA-J <= 3.20 Mitsubishi Electric PAC-YG50ECA <= 2.20 Mitsubishi Electric TE-50A <= 7.93 Mitsubishi Electric TE-200A <= 7.93 Mitsubishi Electric TW-50A <= 7.93

affected: vendor fix, mitigation “G-50A: Version 3.37 or later”

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

0.85% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.1	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N
NVD	2.0	5.5	AV:N/AC:L/Au:S/C:P/I:P/A:N

Affected products

n/a Air Conditioning System/Centralized Controllers G-50A; GB-50A; AG-150A-A; AG-150A-J; GB-50ADA-A; GB-50ADA-J; EB-50GU-A; EB-50GU-J; AE-200A; AE-200E; AE-50A; AE-50E; EW-50A; EW-50E; TE-200A; TE-50A; TW-50A; CMS-RMD-J; Air Conditioning System/Expansion Controllers PAC-YG50ECA

Classification

Weakness

CWE-287 Improper Authentication

References

mitsubishielectric.com /en/psirt/vulnerability/pdf/2021-004_en.pdf
vendor-advisory
jvn.jp /vu/JVNVU96046575/index.html
third-party-advisory

Sources

CVE List CVE-2021-20593
NVD CVE-2021-20593

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