What is the CVSS score of CVE-2026-21657?

CVE-2026-21657 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.1%.

Which versions of Frick Controls Quantum Hd Firmware are affected by CVE-2026-21657?

A critical code injection vulnerability in Johnson Controls Frick Controls Quantum HD (CVSS 9.8) allows unauthenticated attackers to execute arbitrary code on affected systems.

How to fix or mitigate CVE-2026-21657?

Within 24 hours: Identify all Frick Controls Quantum HD deployments in your environment and assess network exposure. Immediately isolate affected systems from internet-facing networks and restrict access to trusted administrators only. Within 7 days: Implement network segmentation to limit lateral movement, enable comprehensive logging on affected systems, and establish daily vulnerability scanning. Within 30 days: Contact Johnson Controls for patch availability and timeline; evaluate replacement or upgrade options if patch delays exceed acceptable risk tolerance; conduct threat hunt for indicators of compromise on affected systems.

Frick Controls Quantum Hd Firmware CVE-2026-21657

CRITICAL

Code Injection (CWE-94)

2026-02-27 productsecurity@jci.com

Code Injection Frick Controls Quantum Hd Firmware

9.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.8 CRITICAL

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:55 vuln.today

CVE Published

Feb 27, 2026 - 09:16 nvd

CRITICAL 9.8

DescriptionCVE.org

Improper Control of Generation of Code ('Code Injection') vulnerability in Johnson Controls Frick Controls Quantum HD allows Code Injection. Insufficient validation of input in certain parameters may permit unexpected actions, which could impact the security of the device before authentication occurs.This issue affects Frick Controls Quantum HD version 10.22 and prior.

AnalysisAI

Second code injection vulnerability in Johnson Controls Frick Controls Quantum HD. Separate attack vector from CVE-2026-21656, same critical impact on industrial refrigeration control.

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access

Send malicious input to unauthenticated endpoint

Exploit

Bypass input validation

Execution

Inject arbitrary code

Impact

Execute code with device privileges

Access

Send malicious input to unauthenticated endpoint

Exploit

Bypass input validation

Execution

Inject arbitrary code

Impact

Execute code with device privileges

Vulnerability AssessmentAI

Exploitation	Johnson Controls Frick Controls Quantum HD version 10.22 or earlier with accessible network interface; no authentication required. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment	CVSS 9.8. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario	Alternative code injection path for achieving RCE on the refrigeration controller.
Remediation	Apply all Johnson Controls security patches simultaneously. Detailed patch versions, workarounds, and compensating controls in full report.