Critical severity · published Jul 31, 2026
CVE-2026-21662
FMS Employee Allows Upload of Unrestricted Files
9.8
CVSS
0.5%
EPSS
No
On KEV
Description
Unrestricted upload of file with dangerous type vulnerability in Johnson Controls FM Systems Employee allows Using Malicious Files.
This issue affects FM Systems Employee: before 2025.3.1.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 43% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FS
FM Systems Employee · Johnson Controls
before 2025.3.1 · source: vendor
FE
Fms Employee · Johnsoncontrols
through 2025.3.1 · source: NVD
In the news
VulnerabilityLow
Johnson Controls OpenBlue Employee
View CSAF
Summary
Successful exploitation of these vulnerabilities could allow an attacker to upload malicious files, execute stored cross-site scripting attacks, or inject arbitrary HTML content.
The following versions of Johnson Controls OpenBlue Employee are affected:
OpenBlue Employee (FMS Employee) <=V2025.3.1 (CVE-2026-21662, CVE-2026-34495, CVE-2026-34497)
CVSS
Vendor
Equipment
Vulnerabilities
v3 2.4
Johnson Controls Inc.
Johnson Controls OpenBlue Employee
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)
Background
Critical Infrastructure Sectors: Critical Manufacturing, Commercial Facilities, Government Services and Facilities, Transportation Systems, Energy
Countries/Areas Deployed: Worldwide
Company Headquarters Location: Ireland
Vulnerabilities
Expand All +
CVE-2026-21662
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.
View CVE Details
Affected Products
Johnson Controls OpenBlue Employee
Vendor: Johnson Controls Inc.
Product Version: Johnson Control...
Jul 30, 2026·CISA Advisories
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-21662
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-21662
Vendor Advisory
https://www.johnsoncontrols.com/trust-center/cybersecurity/security-advisories
More from FM Systems Employee
5.4
CVE-2026-34497
FMS Employee Vulnerable to HTML Injection
5.4
CVE-2026-34495
FMS Employee vulnerable to XSS
