CVE-2023-4804VulnerabilityPublished 10 Nov 2023Updated 16 Dec 2025

CVE-2023-4804: Johnson Controls Quantum HD Unity Compressor · Active Debug Code

Affects Johnson Controls Quantum HD Unity CompressorSource CVE Database V5

Not known to be exploited · CVSS 10.0 Critical.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

10.0Critical

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

EPSS: 0.8% chance of exploitation in 30 days – higher than 56% 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:C/C:H/I:H/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Changed
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: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
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 10 Nov 2023
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
Johnson Controls Quantum HD Unity Compressor	Affected =0	Fixed in–

AI-suggested

1. Immediately isolate Quantum HD Unity Compressor devices from untrusted networks, especially the internet, to prevent unauthorized remote access. 2. Implement strict network segmentation and firewall rules to restrict access to these devices only to authorized personnel and management systems. 3. Monitor network traffic and device logs for unusual access patterns or attempts to use debug features. 4. Engage with Johnson Controls for official patches or firmware updates addressing this vulnerability and apply them promptly once available. 5. Conduct an inventory of all affected devices within the organization to ensure comprehensive coverage of mitigation efforts. 6. Disable or remove any debug or test features manually if vendor guidance is provided. 7. Incorporate this vulnerability into incident response plans and conduct tabletop exercises simulating exploitation scenarios. 8. Educate facility management and IT teams about the risks and signs of compromise related to this vulnerability. 9. Consider deploying intrusion detection/prevention systems (IDS/IPS) tuned to detect exploitation attempts targeting debug interfaces. 10. Review and enhance physical security controls to prevent local access to devices that could facilitate exploitation.

Description

CVE-2023-4804 is a critical vulnerability in Johnson Controls Quantum HD Unity Compressor products where unauthorized users can access active debug features that were unintentionally exposed. This flaw allows remote attackers to gain full control over the affected devices without any authentication or user interaction. Exploitation can lead to complete compromise of confidentiality, integrity, and availability of the system. The vulnerability has a CVSS score of 10.0, indicating maximum severity. No known exploits are currently reported in the wild, but the risk remains high due to ease of exploitation and critical impact. European organizations using these HVAC control systems could face operational disruptions and data breaches. Immediate mitigation involves restricting network access to these devices, applying vendor patches once available, and monitoring for unusual activity. Countries with significant deployments of Johnson Controls products and critical infrastructure relying on HVAC systems are at higher risk. Given the critical nature and potential for widespread impact, this vulnerability demands urgent attention from defenders.

Impact

For European organizations, the impact of CVE-2023-4804 can be severe. Johnson Controls HVAC systems are widely used in commercial buildings, data centers, hospitals, and industrial facilities across Europe. Exploitation could lead to unauthorized control over environmental conditions, causing operational disruptions, safety hazards, and potential damage to sensitive equipment. Confidential data managed or transmitted by these systems could be exposed or manipulated, leading to breaches of privacy and compliance violations under regulations like GDPR. The integrity of building automation could be compromised, allowing attackers to disable or alter system functions. Availability impacts could result in downtime of critical infrastructure, affecting business continuity and public safety. Additionally, compromised devices could serve as entry points for lateral movement within corporate or industrial networks, amplifying the risk of broader cyberattacks. The critical severity and ease of exploitation necessitate immediate risk assessment and mitigation by European entities relying on these products.

Summary

CVE-2023-4804 is a critical security vulnerability identified in the Johnson Controls Quantum HD Unity Compressor, a product used in HVAC and building management systems. The root cause is the presence of active debug code that was accidentally left enabled and exposed in production devices. This debug functionality can be accessed by unauthorized users remotely without requiring any authentication or user interaction, making exploitation straightforward. The vulnerability is classified under CWE-489 (Active Debug Code), which refers to debug features that remain active in production software and can be abused by attackers. The CVSS v3.1 base score is 10.0, reflecting the highest severity due to network attack vector (AV:N), no required privileges (PR:N), no user interaction (UI:N), and complete impact on confidentiality, integrity, and availability (C:H/I:H/A:H). An attacker exploiting this vulnerability could gain full control over the affected device, potentially manipulating HVAC operations, disrupting building environments, or using the device as a pivot point for further network intrusion. Although no public exploits have been reported yet, the vulnerability’s characteristics make it a prime target for attackers. The lack of available patches at the time of publication increases the urgency for interim mitigations such as network segmentation and access controls. This vulnerability highlights the risks of deploying embedded systems with leftover debug code in critical infrastructure environments.

CWE-489Active Debug Code (opens in a new tab)
Base weaknessOWASP Top 10 A02:2025: Security Misconfiguration (opens in a new tab)
The product is released with debugging code still enabled or active.
Build and Compilation · Distribution
Remove debug code before deploying the application.
Attack patterns
Exploit Non-Production Interfaces (opens in a new tab)
Root/Jailbreak Detection Evasion via Debugging (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 23 Dec 2025, 18:34 UTC

WeaknessesCWE-489

Technical details

References

Community reviews

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