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 Johnsoncontrols

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

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.