How severe is CVE-2021-20593?

CVE-2021-20593 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability none.

Is CVE-2021-20593 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20593?

CVE-2021-20593 primarily affects Mitsubishi G-50a Firmware. In total, 19 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-20593?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-20593 published?

CVE-2021-20593 was published on 2021-07-13 and last updated on 2026-06-17.

CVE-2021-20593

CVE-2021-20593 is a high-severity vulnerability in Mitsubishi G-50a Firmware with a CVSS 3.x base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

Severity: High (CVSS 3.x base score 7.1)
CVSS v2: 5.5
EPSS exploit prediction: 1% (54th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Mitsubishi G-50a Firmware
Published: 2021-07-13
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2021-20593?: CVE-2021-20593 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability none.
Is CVE-2021-20593 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20593?: CVE-2021-20593 primarily affects Mitsubishi G-50a Firmware. In total, 19 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-20593?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-20593 published?: CVE-2021-20593 was published on 2021-07-13 and last updated on 2026-06-17.

References

Affected products (19)

cpe:2.3:o:mitsubishi:g-50a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:gb-50a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:ag-150a-a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:ag-150a-j_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:gb-50ada-a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:gb-50ada-j_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:eb-50gu-a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:eb-50gu-j_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:ae-200a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:ae-200e_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:ae-50a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:ae-50e_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:ew-50a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:ew-50e_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:te-200a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:te-50a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:tw-50a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:cms-rmd-j_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mitsubishi:pac-yg50eca_firmware:*:*:*:*:*:*:*:*

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