What is the CVSS score of CVE-2026-21660?

CVE-2026-21660 has a CVSS 4.0 base score of 6.9 (Medium). CVSS vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N. EPSS exploitation probability: 0.0%.

How to fix or mitigate CVE-2026-21660?

Within 24 hours: Identify all Frick Controls Quantum HD installations and document current firmware versions; restrict network access to affected systems to essential personnel only; begin credential rotation for all email accounts potentially affected. Within 7 days: Implement network segmentation to isolate affected systems from critical infrastructure; deploy enhanced monitoring for unauthorized access attempts; engage Frick Controls support for guidance on firmware upgrades or alternatives. Within 30 days: Deploy patched firmware versions once available from vendor; conduct forensic analysis of system logs for evidence of unauthorized access; implement secrets management solution for any replacement systems.

Frick Controls Quantum Hd Firmware CVE-2026-21660

MEDIUM

Plaintext Storage of a Password (CWE-256)

2026-02-27 productsecurity@jci.com

Authentication Bypass Frick Controls Quantum Hd Firmware Johnsoncontrols

6.9

CVSS 4.0 · Vendor: jci

View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Obtain firmware image from Frick Controls Quantum HD
Exploit

Extract hardcoded email credentials from plaintext storage
Execution

Authenticate using exposed credentials
Impact

Access system with obtained privileges

Vulnerability Assessment

Weakness	CWE CWE-256 OWASP Top 10:2025 A06:2025 - Insecure Design ASVS 5.0 V6 - Authentication Credential storage protection
Exploitation Conditions	Attacker must have access to firmware binary (via device physical extraction, firmware download, or network interception). Frick Controls Quantum HD version 10.22 and earlier stores email credentials in plaintext without encryption in firmware. No authentication required to extract firmware if accessible through device storage or update mechanisms.
Impact	CVSS 9.8. Hardcoded credentials in ICS firmware are persistent — they cannot be changed by end users and affect all deployments.
Exploit ScenarioDerived	Attacker extracts firmware image, retrieves hardcoded email credentials, uses them to access the email service for phishing, data exfiltration, or as pivot for further attacks.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

No patch listed yet 0.0% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAIv1 – Mar 12, 2026

Hardcoded email credentials stored as plaintext in Johnson Controls Frick Controls firmware. Sixth critical vulnerability — exposed credentials could enable account access and lateral movement.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:55 CVSS 9.8

Hardcoded plaintext email credentials in Frick Controls firmware.

RemediationAI

Contact Johnson Controls for firmware update with credential management fix. Rotate any email service credentials if possible.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

CWE-256 plaintext password storage. Email service credentials are hardcoded in the firmware, extractable by anyone with access to the firmware image.

Know when Frick Controls Quantum Hd Firmware gets its next vulnerability

Watch products and get an email when something new is published
Check this CVE against your own stack and servers
Exploit and PoC references, threat intelligence from 22 sources

Continue with Google Continue with GitHub

No credit card · 7-day full trial

Severity by source

Vendor (jci) PRIMARY 6.9 MEDIUM

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (jci) · only source for this CVE.

CVSS VectorVendor: jci

Attack Vector

Local

Attack Complexity

Low

Attack Requirements

None

Privileges Required

None

User Interaction

None

Vulnerable system: Confidentiality

High

Vulnerable system: Integrity

None

Vulnerable system: Availability

None

Subsequent system: Confidentiality

None

Subsequent system: Integrity

None

Subsequent system: Availability

None

Lifecycle Timeline

Severity Changed

Aug 24, 2026 - 18:22 NVD

CRITICAL MEDIUM

CVSS changed

Aug 24, 2026 - 18:22 NVD

9.8 (CRITICAL) 6.9 (MEDIUM)

CVE Published

Feb 27, 2026 - 10:16 nvd

CRITICAL 9.8

DescriptionCVE.org

Hardcoded Email Credentials Saved as Plaintext in Firmware (CWE-256: Plaintext Storage of a Password) vulnerability in Frick Controls Quantum HD version 10.22 and prior lead to unauthorized access, exposure of sensitive information, and potential misuse or system compromise This issue affects Frick Controls Quantum HD version 10.22 and prior.

Executive ViewAI

Why It Matters

Frick Controls Quantum HD firmware versions 10.22 and prior contain hardcoded email credentials stored in plaintext, creating a critical risk of unauthorized system access and data exposure. Any organization running affected HVAC control systems faces immediate compromise risk, as attackers can extract credentials from firmware and gain full system control without detection.

Business Impact: Severe

Compensating Controls

Network segmentation: isolate Quantum HD systems on dedicated VLAN with restricted egress; Disable email functionality if not operationally critical; Monitor all outbound SMTP connections from affected systems for anomalous activity; Implement strict firewall rules limiting system communication to known trusted hosts; Require VPN access for remote connections to affected devices; Enable verbose logging and centralized SIEM ingestion; Prepare vendor communication to request available firmware patches or end-of-life guidance; Consider temporary operational workarounds until patched firmware is available.

Threat Intelligence Overview

EPSS Score

0.0%

Top 87% exploitable

Data Quality

3 sources

Confidence: Low

NVD

CVE.org

EPSS

VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity MEDIUM

CISA KEV No

Public POC No

EPSS 0.0%

Patch available No

Active threat No

Deciding rule

MEDIUM severity (CVSS 4.0-6.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.