CVE-2025-3699VulnerabilityPublished 26 Jun 2025Updated 23 Dec 2025

CVE-2025-3699: Mitsubishi Electric G-50 · Missing Authentication

Affects Mitsubishi Electric G-50Source CVE Database V5

Not known to be exploited · CVSS 9.8 Critical.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

9.8Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 1.1% chance of exploitation in 30 days – higher than 66% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 26 Jun 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Mitsubishi Electric Corporation G-50	Affected *	Fixed in–

AI-suggested

Given the absence of official patches, European organizations should implement the following specific mitigations: 1) Isolate Mitsubishi G-50 HVAC systems on dedicated network segments with strict firewall rules restricting access to trusted management hosts only. 2) Employ network intrusion detection and prevention systems (IDS/IPS) to monitor and block anomalous traffic targeting HVAC control protocols. 3) Enforce strong physical security to prevent unauthorized local access to devices. 4) Disable any unnecessary remote management interfaces or protocols on the affected devices. 5) Use VPNs or secure tunnels for any remote access to HVAC systems to add an authentication layer. 6) Regularly audit and monitor device logs for signs of unauthorized access or firmware changes. 7) Engage with Mitsubishi Electric Corporation for timely updates and advisories. 8) Develop incident response plans specific to HVAC system compromise scenarios. 9) Consider deploying compensating controls such as network segmentation combined with multi-factor authentication for management interfaces where possible. 10) Educate facility management and IT staff about the risks and signs of exploitation to ensure prompt detection and response.

Description

Missing Authentication for Critical Function vulnerability in Mitsubishi Electric Corporation G-50 all versions, G-50-W all versions, G-50A all versions, GB-50 all versions, GB-50A all versions, GB-24A all versions, G-150AD all versions, AG-150A-A all versions, AG-150A-J all versions, GB-50AD all versions, GB-50ADA-A all versions, GB-50ADA-J all versions, EB-50GU-A all versions, EB-50GU-J all versions, AE-200J all versions, AE-200A all versions, AE-200E all versions, AE-50J all versions, AE-50A all versions, AE-50E all versions, EW-50J all versions, EW-50A all versions, EW-50E all versions, TE-200A all versions, TE-50A all versions, TW-50A all versions, and CMS-RMD-J all versions allows a remote unauthenticated attacker to bypass authentication and then control the air conditioning systems illegally, or disclose information in them by exploiting this vulnerability. In addition, the attacker may tamper with firmware for them using the disclosed information.

Impact

For European organizations, the impact of CVE-2025-3699 is substantial. Unauthorized control over HVAC systems can lead to operational disruptions, affecting climate control in data centers, manufacturing plants, hospitals, and office buildings, potentially causing equipment damage or health hazards. Disclosure of sensitive configuration or operational data could aid further attacks or industrial espionage. Firmware tampering risks persistent compromise, enabling attackers to maintain access or cause physical damage. Critical infrastructure facilities relying on Mitsubishi HVAC systems may face safety and regulatory compliance issues. The disruption of environmental controls in sensitive environments could lead to cascading failures in other systems, amplifying the impact. Additionally, the lack of authentication increases the attack surface, making these systems attractive targets for cybercriminals or nation-state actors. The absence of patches necessitates immediate compensating controls to mitigate risk. Overall, the vulnerability threatens confidentiality, integrity, and availability of critical environmental control systems across multiple sectors in Europe.

Summary

CVE-2025-3699 is a critical security vulnerability classified under CWE-306 (Missing Authentication for Critical Function) affecting all versions of Mitsubishi Electric Corporation's G-50 series air conditioning control systems, including multiple variants such as G-50-W, G-50A, GB-50, AE-200 series, and others. The flaw allows a remote attacker to bypass authentication mechanisms entirely, enabling unauthorized access to critical functions of the HVAC systems without any user interaction or prior privileges. This unauthorized access can lead to full control over the air conditioning units, including the ability to manipulate operational parameters, disrupt service availability, and disclose sensitive system information. Furthermore, the attacker may leverage the disclosed information to tamper with or replace device firmware, potentially establishing persistent control or causing long-term damage. The vulnerability is remotely exploitable over the network (AV:N), requires no privileges (PR:N), no user interaction (UI:N), and affects confidentiality, integrity, and availability to a high degree (C:H/I:H/A:H), resulting in a CVSS v3.1 score of 9.8. Despite the severity, no patches or mitigations have been released at the time of publication, and no active exploitation has been reported. This vulnerability poses a significant risk to environments where these HVAC systems are deployed, particularly in industrial, commercial, and critical infrastructure sectors where environmental controls are essential for operational stability and safety.

CWE-306Missing Authentication for Critical Function (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #21OWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.
Architecture and Design
Divide the software into anonymous, normal, privileged, and administrative areas. Identify which of these areas require a proven user identity, and use a centralized authentication capability.
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks…
Architecture and Design
Where possible, avoid implementing custom, "grow-your-own" authentication routines and consider using authentication capabilities as provided by the surrounding framework, operating system, or environment.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V1.2.3 (opens in a new tab)
V1.2.2 (opens in a new tab)
V1.2.4 (opens in a new tab)
Attack patterns
Choosing Message Identifier (opens in a new tab)
Force the System to Reset Values (opens in a new tab)
Using Unpublished Interfaces or Functionality (opens in a new tab)
Cross Site Request Forgery (opens in a new tab)
Communication Channel Manipulation (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 23 Dec 2025, 00:47 UTC

WeaknessesCWE-306

Technical details

References

Community reviews

Related threats