Cyber Posture

CVE-2026-21656

Critical

Published: 27 February 2026

Published
27 February 2026
Modified
02 March 2026
KEV Added
—
Patch
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CVSS Score 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0014 33.3th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Description

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…

more

occurs.This issue affects Frick Controls Quantum HD version 10.22 and prior.

Mitigating Controls (NIST 800-53 r5)AI

SI-10 Information Input Validation good match
prevent

Directly addresses the insufficient input validation causing code injection by requiring checks at input points to prevent malicious code execution.

SI-2 Flaw Remediation good match
prevent

Mandates timely remediation of the known code injection flaw in Quantum HD version 10.22 and prior via patching as advised by CISA and Johnson Controls.

AC-14 Permitted Actions Without Identification or Authentication partial match
prevent

Limits permitted actions without authentication, mitigating pre-authentication code injection impacts by restricting unauthenticated input processing.

Security SummaryAI

CVE-2026-21656 is an Improper Control of Generation of Code ('Code Injection') vulnerability, classified under CWE-94, in Johnson Controls Frick Controls Quantum HD. The flaw arises from insufficient validation of input in certain parameters, enabling code injection that can perform unexpected actions and impact device security before authentication occurs. This issue affects Frick Controls Quantum HD version 10.22 and prior versions.

The vulnerability carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating it is exploitable over the network with low attack complexity, no privileges or user interaction required, and unchanged impact scope. Unauthenticated remote attackers can leverage it to inject code, achieving high impacts on confidentiality, integrity, and availability of the affected device.

Advisories from CISA (ICSA-26-057-01) and Johnson Controls' trust center cybersecurity security advisories provide guidance on mitigation. Security practitioners should review these references for details on available patches, workarounds, or other protective measures.

Details

CWE(s)
CWE-94

Affected Products

johnsoncontrols
frick controls quantum hd firmware
≤ 10.22

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Why these techniques?

The vulnerability allows unauthenticated remote code injection over the network in a public-facing device application, directly mapping to exploitation of public-facing applications.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

References