CVE-2026-21656 Johnson Controls -Frick Quantum HD- Unauthenticated Remote Code Execution

High 8.8 Published 27 Feb 2026 Updated 6 Mar 2026

Unauthenticated attackers can execute arbitrary code on Johnson Controls Frick Controls Quantum HD devices via improper input validation.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-21656?

CVE-2026-21656 is a high-severity code injection vulnerability in Johnson Controls Frick Controls Quantum HD, published on 27 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

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

Weakness: CWE-94

Which versions are affected by CVE-2026-21656?

It affects 1 product.

Products include Johnsoncontrols Frick Controls Quantum Hd Firmware.

How do I fix CVE-2026-21656?

No fix has been published for CVE-2026-21656 yet. Limit exposure of the affected software until one is available.

Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.

Is CVE-2026-21656 being exploited?

There is no known exploitation of CVE-2026-21656 in the wild and no public exploit code.

Sources

Also known as GHSA-jhjg-8mcj-cvjp.