CVE-2021-20593

What it is

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.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account. High risk of data tampering.

Exploit odds

0.9% chance of exploitation in the next 30 days (EPSS).

Fix

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

Timeline

1. 2021-07-13 14:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 03:34 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.9% in the next 30 days (EPSS).
• Severity: 7.1 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-07-13 14:15 UTC

Last modified

2026-06-17 03:34 UTC

Exploit probability

0.9% · EPSS, next 30 days

Weakness

CWE-287 · Improper authentication

Record status

Modified

Affected

• Mitsubishi g-50a Firmware ≤ 3.35
• Mitsubishi gb-50a Firmware ≤ 3.35
• Mitsubishi ag-150a-a Firmware ≤ 3.20
• Mitsubishi ag-150a-j Firmware ≤ 3.20
• Mitsubishi gb-50ada-a Firmware ≤ 3.20
• Mitsubishi gb-50ada-j Firmware ≤ 3.20
• Mitsubishi eb-50gu-a Firmware ≤ 7.09
• Mitsubishi eb-50gu-j Firmware ≤ 7.09

Attack profile CVSS 3.1 · 7.1

Attack vector

Network

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

High

Availability

None

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