Cyber Posture

CVE-2026-21657

Critical

Published: 27 February 2026

Published
27 February 2026
Modified
02 March 2026
KEV Added
Patch
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

prevent

SI-10 directly addresses the root cause of CVE-2026-21657 by requiring comprehensive input validation to prevent code injection from insufficiently validated parameters.

prevent

SI-2 ensures timely patching and flaw remediation as outlined in the vendor and CISA advisories, preventing exploitation of the code injection vulnerability in affected versions.

prevent

AC-14 limits permitted actions without authentication, mitigating pre-authentication code injection that impacts device security via unexpected actions on unauthenticated inputs.

Security SummaryAI

CVE-2026-21657 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, which may permit unexpected actions that impact the security of the device 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 remotely over the network by unauthenticated attackers requiring low complexity and no user interaction. Successful exploitation enables code injection, resulting in high impacts to confidentiality, integrity, and availability of the affected device.

Mitigation details are outlined in the CISA ICS Advisory ICSA-26-057-01 (https://www.cisa.gov/news-events/ics-advisories/icsa-26-057-01) and the Johnson Controls security advisory (https://www.johnsoncontrols.com/trust-center/cybersecurity/security-advisories).

Details

CWE(s)

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.
Why these techniques?

The vulnerability is a pre-authentication code injection flaw in a network-accessible ICS device, directly enabling exploitation of a public-facing application.

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

References