How severe is CVE-2026-21656?

CVE-2026-21656 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-21656 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-21656?

CVE-2026-21656 affects Johnsoncontrols Frick Controls Quantum Hd Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-21656?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-21656 have an EU (EUVD) identifier?

Yes. CVE-2026-21656 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-9011.

When was CVE-2026-21656 published?

CVE-2026-21656 was published on 2026-02-27 and last updated on 2026-06-17.

CVE-2026-21656

CVE-2026-21656 is a critical-severity vulnerability in Johnsoncontrols Frick Controls Quantum Hd Firmware with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-94.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 8.8
EPSS exploit prediction: 0% (33rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-9011
Weakness: CWE-94
Affected product: Johnsoncontrols Frick Controls Quantum Hd Firmware
Published: 2026-02-27
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-21656?: 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.
How severe is CVE-2026-21656?: CVE-2026-21656 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-21656 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-21656?: CVE-2026-21656 affects Johnsoncontrols Frick Controls Quantum Hd Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-21656?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-21656 have an EU (EUVD) identifier?: Yes. CVE-2026-21656 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-9011.
When was CVE-2026-21656 published?: CVE-2026-21656 was published on 2026-02-27 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:johnsoncontrols:frick_controls_quantum_hd_firmware:*:*:*:*:*:*:*:*

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