Security readout for executives and security teams
Plain-English summary
Frick Controls Quantum HD firmware stores hardcoded email credentials in plaintext. Anyone able to access the vulnerable firmware or affected system locally may recover those credentials, potentially exposing sensitive email information or enabling misuse. Quantum HD version 10.22 and earlier is affected.
Executive priority
Treat this as a planned, near-term industrial security remediation. Prioritize sites using affected versions where controllers, firmware, or maintenance environments are broadly accessible. Escalate if associated email accounts contain sensitive operational information or show suspicious access.
Technical view
CVE-2026-21660 is a CWE-256 plaintext password storage flaw in Frick Controls Quantum HD 10.22 and earlier. CVSS 4.0 scores it 6.9 with local access, low complexity, no privileges, and no user interaction. The stated impact is high confidentiality loss without demonstrated integrity or availability impact.
Likely exposure
Exposure is limited to organizations operating Frick Controls Quantum HD version 10.22 or earlier. The local attack vector reduces broad remote risk, but shared credentials, accessible firmware, weak physical controls, or compromised maintenance systems could increase practical exposure.
Exploitation context
The supplied sources do not establish active exploitation, and this CVE is not listed as KEV in the bundle. Exploitation requires local access according to the CVSS vector. No public exploit method or observed campaign is identified in the provided evidence.
Researcher notes
The evidence clearly identifies affected versions and plaintext credential storage, but does not specify the credential scope, vendor-fixed version, patch, or detailed mitigation. CVSS indicates local exploitation and confidentiality impact only. Validate remediation details directly against current Johnson Controls and CISA advisories.
Mitigation direction
- Inventory Quantum HD systems and identify installations running version 10.22 or earlier.
- Review Johnson Controls and CISA guidance for an approved update or vendor mitigation.
- Restrict physical and administrative access to controllers, firmware files, and maintenance systems.
- Rotate exposed email credentials where safely supported and coordinate changes with Johnson Controls.
- Monitor the associated email account for suspicious authentication or access activity.
Validation and detection
- Confirm each Quantum HD firmware version using approved asset-management or maintenance procedures.
- Verify vulnerable controllers are segmented and accessible only by authorized personnel and systems.
- Confirm vendor-recommended updates or mitigations have been applied without disrupting industrial operations.
- Review relevant email and controller logs for unexplained authentication or access events.
- Ensure recovered credentials are handled securely and never recorded in plaintext assessment reports.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-256: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-21660 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.9 (4.0)
- Known Exploited
- No
- Published
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
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
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——jciVulnerability scoring details
Base CVSS 4.0 score
6.9MediumVector: 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
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://www.cisa.gov/news-events/ics-advisories/icsa-26-057-01CVE reference, jci
- https://www.johnsoncontrols.com/trust-center/cybersecurity/security-advisoriesCVE reference, jci
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Plaintext Storage of a Password
Plaintext Storage of a Password represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.