Room Air Conditioners (for Japan) MSZ-BKR2223-W: Use of Hard-coded Credentials
CVE-2026-5667 is a high-severity use of hard-coded credentials vulnerability in Room Air Conditioners (for Japan) MSZ-BKR2223-W from Mitsubishi Electric, with a CVSS 4.0 base score of 7.2 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. Affected Room Air Conditioners (for Japan) MSZ-BKR2223-W versions: 42.00 and prior. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.15% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Room Air Conditioners (for Japan) MSZ-BKR2223-W you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on mitsubishielectric.com for workarounds and exact fixed builds.
Affected products and versions
Version data comes from the organisation that assigned the CVE; 35 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- AdjacentThe attacker must be on the same local network segment.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Attack requirements
- NoneThe attack does not depend on a particular deployment or configuration.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Confidentiality (vulnerable system)
- HighSerious loss of confidentiality on the vulnerable system.
- Integrity (vulnerable system)
- LowLimited loss of integrity on the vulnerable system.
- Availability (vulnerable system)
- LowLimited loss of availability on the vulnerable system.
- Confidentiality (other systems)
- NoneNo loss of confidentiality on systems beyond the vulnerable one.
- Integrity (other systems)
- NoneNo loss of integrity on systems beyond the vulnerable one.
- Availability (other systems)
- NoneNo loss of availability on systems beyond the vulnerable one.
Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA (yd.MitsubishiElectric.co.jp).
Official description
Use of Hard-coded Credentials vulnerability in Mitsubishi Electric Room Air Conditioners (for Japan and outside Japan); Wireless LAN Adapters for Room Air Conditioners (for Japan and outside Japan); Wireless LAN Adapters for Packaged Air Conditioners (for Japan and outside Japan); Refrigerators (for Japan); Heat Pump Water Heaters / HEMS-Compatible Adapters / Wireless LAN Adapters (for Japan); Bathroom Dryer / Heater / Ventilation Systems (for Japan); Adapters for Airflow Ventilation Systems, Heat Pump Chilled / Hot Water Systems, and Ventilation / Air-Conditioning System Air Resorts (for Japan); Lossnay Central Ventilation Systems (for Japan); Smart Switches for Ventilation Fans and Lossnay (for Japan); IH Cooking Heaters (for Japan); and Rice Cookers (for Japan) allows an attacker within Wi-Fi radio range of an affected product to access the affected product using a hard-coded SSID and password, thereby obtaining device data such as operation status, room set temperature, and room temperature; changing the air-conditioner or Wi-Fi settings; or causing Wi-Fi communication to enter a denial-of-service (DoS) condition.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Hard-coded Credentials
The product contains hard-coded credentials, such as a password or cryptographic key.
How developers prevent this class of flaw
- For outbound authentication: store passwords, keys, and other credentials outside of the code in a strongly-protected, encrypted configuration file or database that is protected from access by all outsiders, including other local users on the same system. Properly protect the key (CWE-320). If you cannot use encryption to protect the file, then make sure that the permissions are as restrictive as possible. In Windows environments, the Encrypted File System (EFS) may provide some protection.
- For inbound authentication: Rather than hard-code a default username and password, key, or other authentication credentials for first time logins, utilize a first login mode that requires the user to enter a unique strong password or key.
- If the product must contain hard-coded credentials or they cannot be removed, perform access control checks and limit which entities can access the feature that requires the hard-coded credentials. For example, a feature might only be enabled through the system console instead of through a network connection.
More Use of Hard-coded Credentials vulnerabilities (CWE-798)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
References
Other references
Recent Use of Hard-coded Credentials vulnerabilities
- 8.6 High severity
- 7.4 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
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