CVE-2021-20593

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.

Published: 2021-07-13 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-20593 is rated Moderate Risk (45.9/100): CVSS High severity, with low exploitation likelihood (EPSS 0.26%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-20593

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-04 0.14% 0.26% +0.12%
2 2025-11-21 0.15% 0.14% -0.01%
3 2025-11-18 — 0.15% —

Full EPSS history (10 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-20593

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.1 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 4.2 [email protected]
5.5 2.0 MEDIUM
AV:N/AC:L/Au:S/C:P/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 8.0 4.9 [email protected]

Weakness enumeration for CVE-2021-20593

Affected software / configurations for CVE-2021-20593

Vendor Product Version Raw CPE
mitsubishi g-50a_firmware >= 2.50, <= 3.35 cpe:2.3:o:mitsubishi:g-50a_firmware:*:*:*:*:*:*:*:*
mitsubishi gb-50a_firmware >= 2.50, <= 3.35 cpe:2.3:o:mitsubishi:gb-50a_firmware:*:*:*:*:*:*:*:*
mitsubishi ag-150a-a_firmware <= 3.20 cpe:2.3:o:mitsubishi:ag-150a-a_firmware:*:*:*:*:*:*:*:*
mitsubishi ag-150a-j_firmware <= 3.20 cpe:2.3:o:mitsubishi:ag-150a-j_firmware:*:*:*:*:*:*:*:*
mitsubishi gb-50ada-a_firmware <= 3.20 cpe:2.3:o:mitsubishi:gb-50ada-a_firmware:*:*:*:*:*:*:*:*
mitsubishi gb-50ada-j_firmware <= 3.20 cpe:2.3:o:mitsubishi:gb-50ada-j_firmware:*:*:*:*:*:*:*:*
mitsubishi eb-50gu-a_firmware <= 7.09 cpe:2.3:o:mitsubishi:eb-50gu-a_firmware:*:*:*:*:*:*:*:*
mitsubishi eb-50gu-j_firmware <= 7.09 cpe:2.3:o:mitsubishi:eb-50gu-j_firmware:*:*:*:*:*:*:*:*
mitsubishi ae-200a_firmware <= 7.93 cpe:2.3:o:mitsubishi:ae-200a_firmware:*:*:*:*:*:*:*:*
mitsubishi ae-200e_firmware <= 7.93 cpe:2.3:o:mitsubishi:ae-200e_firmware:*:*:*:*:*:*:*:*
mitsubishi ae-50a_firmware <= 7.93 cpe:2.3:o:mitsubishi:ae-50a_firmware:*:*:*:*:*:*:*:*
mitsubishi ae-50e_firmware <= 7.93 cpe:2.3:o:mitsubishi:ae-50e_firmware:*:*:*:*:*:*:*:*
mitsubishi ew-50a_firmware <= 7.93 cpe:2.3:o:mitsubishi:ew-50a_firmware:*:*:*:*:*:*:*:*
mitsubishi ew-50e_firmware <= 7.93 cpe:2.3:o:mitsubishi:ew-50e_firmware:*:*:*:*:*:*:*:*
mitsubishi te-200a_firmware <= 7.93 cpe:2.3:o:mitsubishi:te-200a_firmware:*:*:*:*:*:*:*:*
mitsubishi te-50a_firmware <= 7.93 cpe:2.3:o:mitsubishi:te-50a_firmware:*:*:*:*:*:*:*:*
mitsubishi tw-50a_firmware <= 7.93 cpe:2.3:o:mitsubishi:tw-50a_firmware:*:*:*:*:*:*:*:*
mitsubishi cms-rmd-j_firmware <= 1.30 cpe:2.3:o:mitsubishi:cms-rmd-j_firmware:*:*:*:*:*:*:*:*
mitsubishi pac-yg50eca_firmware <= 2.20 cpe:2.3:o:mitsubishi:pac-yg50eca_firmware:*:*:*:*:*:*:*:*

References for CVE-2021-20593

cvelogic Threat Intelligence