Johnson Controls OpenBlue Employee: 3 CVEs, Low 2.4
Summary
CISA reports 3 vulnerabilities in Johnson Controls OpenBlue Employee (FMS Employee). Weakness types: Unrestricted Upload of File with Dangerous Type, Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS). Successful exploitation of these vulnerabilities could allow an attacker to upload malicious files, execute stored cross-site scripting attacks, or inject arbitrary HTML content. Highest CVSS v3 score: 2.4 (Low), exploitable over the network.
At a glance
- Vendor
- Johnson Controls
- Products
- OpenBlue Employee (FMS Employee)
- CVEs
- CVE-2026-21662, CVE-2026-34495, CVE-2026-34497
- Highest CVSS v3
- 2.4 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N
- Highest CVSS v4
- –
- Known exploited (KEV)
- No CVE from this advisory is on the KEV list as of the last refresh
- Sectors (per CISA)
- Critical Manufacturing, Commercial Facilities, Government Services and Facilities, Transportation Systems, Energy
- Deployed
- Worldwide
- Vendor HQ
- Ireland
Vulnerabilities
| CVE | Weakness | CVSS v3 | CVSS v4 | KEV | Description (from advisory) |
|---|---|---|---|---|---|
| CVE-2026-21662 | Unrestricted Upload of File with Dangerous Type | 2.4 | – | No | The application does not adequately restrict the types of files that can be uploaded, allowing an attacker to submit files with dangerous content types. Uploaded files may be stored in predictable locations and could be leveraged for further exploitation against the application or its users. |
| CVE-2026-34495 | Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') | 2.4 | – | No | Stored XSS occurs when the application improperly handles user input and stores malicious JavaScript code within its database. This script is then rendered and executed whenever another user accesses the compromised page. Unlike reflected XSS, persistent XSS is particularly dangerous because the payload remains active until it is manually removed from the system. |
| CVE-2026-34497 | Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS) | 2.4 | – | No | HTML injection occurs when user-controlled input is embedded into web pages without proper encoding or sanitization, allowing attackers to inject arbitrary HTML markup. This vulnerability enables attackers to manipulate the Document Object Model (DOM) structure and alter the visual presentation of web content. Unlike Cross-Site Scripting (XSS), HTML injection typically involves static HTML content… |
Affected products (1)
- Johnson Controls Inc. OpenBlue Employee (FMS Employee): <=V2025.3.1
Vendor fixes and mitigations (from advisory)
- Mitigation: Johnson Controls recommends the following defensive measures to help reduce the risk of exploitation: Apply the latest product update for OpenBlue Employee (FMS Employee). Customers running V2025.3.1 [LV1.1] or earlier should apply the latest available update.
- Mitigation: Limit application access to authorized users and enforce strong authentication.
- Mitigation: Enable the "Do Not Show Files" location setting if the feature is not being actively used.
- Mitigation: Employ a Web Application Firewall (WAF) to help detect and block malicious requests.
- Mitigation: Investigate and promptly remove any suspicious files or content discovered within the application.
- Mitigation: Limit internet exposure by restricting access to trusted networks or VPN users where practical.
- Mitigation: Review uploaded content periodically and remove content that is no longer required.
- Mitigation: For more detailed mitigation instructions, please see Johnson Controls Product Security Advisory JCI-PSA-2026-09 at the following location: https://www.johnsoncontrols.com/trust-center/cybersecurity/security-advisories link
Also apply CISA's standard ICS practices: minimize network exposure, keep control networks behind firewalls and isolated from business networks, and use up-to-date secure remote access.
Sources
This page is generated automatically from the CISA advisory text. It is not a substitute for the vendor's guidance; verify affected versions and fixes at the source before making changes to control systems.