CVE-2026-34491

Cross‑Site Scripting Vulnerability in Johnson Controls Metasys 14 and 15

Published Aug 24, 2026 CVSS 4.0 · 6.1 Medium EPSS < 1% KEV · Not listed
Description
Improper neutralization of input during web page generation ('cross-site scripting') vulnerability in Johnson Controls Metasys 14 and Johnson Controls Metasys 15 allows Cross Site Scripting.

This issue affects Metasys 14: before 14.1.5; Metasys 15: before 15.0.1.

Analysis

AI-generated

Technical impact

The vulnerability is an improper neutralization of user input during web page generation, which allows an attacker to inject malicious scripts that execute in the context of the victim’s browser. This cross‑site scripting flaw enables client‑side code execution, potentially leaking session data, defacing pages, or facilitating phishing attacks. The weakness is classified as CWE‑79.

Affected Systems

Johnson Controls Metasys 14 versions prior to 14.1.5 and Johnson Controls Metasys 15 versions prior to 15.0.1 are affected. These are industrial building automation platforms that provide web‑based management interfaces.

Risk and Exploitability

The CVSS score is 6.1, indicating a high severity. EPSS data is not available, so the likelihood of real‑world exploitation is currently unknown, but cross‑site scripting is a well‑known attack vector. The vulnerability is not listed in CISA’s KEV catalogue, and no public exploit has been reported. Based on the description, it is inferred that the attack vector involves web requests to the Metasys web interface, where crafted input can be supplied and reflected back to users.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Upgrade to Johnson Controls Metasys 14.1.5 or later, or Metasys 15.0.1 or later, which contain the fix for the XSS issue.
  • If immediate upgrade is not possible, restrict external access to the Metasys web interface and enforce strong authentication to limit exposure.
  • Deploy a web application firewall or similar controls to block suspicious script payloads and mitigate potential XSS exploitation.

Generated by OpenCVE AI on August 24, 2026 at 18:39 UTC.

Tracking

Sign in to view the affected projects.

Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Johnsoncontrols
Johnsoncontrols metasys
Vendors & Products Johnsoncontrols
Johnsoncontrols metasys
Type Values Removed Values Added
Title Cross‑Site Scripting Vulnerability in Johnson Controls Metasys 14 and 15
Weaknesses CWE-79
Type Values Removed Values Added
Description Improper neutralization of input during web page generation ('cross-site scripting') vulnerability in Johnson Controls Metasys 14 and Johnson Controls Metasys 15 allows Cross Site Scripting. This issue affects Metasys 14: before 14.1.5; Metasys 15: before 15.0.1.
First Time appeared Johnson Controls
Johnson Controls metasys 14
Johnson Controls metasys 15
CPEs cpe:2.3:a:johnson_controls:metasys_14:*:*:*:*:*:*:*:*
cpe:2.3:a:johnson_controls:metasys_15:*:*:*:*:*:*:*:*
Vendors & Products Johnson Controls
Johnson Controls metasys 14
Johnson Controls metasys 15
References
Metrics cvssV4_0

{'score': 6.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U'}

Weaknesses
  • CWE-79

    Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Sources

Status
PUBLISHED
Assigner
jci
Published
Updated
Aug 25, 2026, 5:33 PM
Reserved
Mar 30, 2026, 8:25 AM
Status
Awaiting Analysis
Published
Aug 24, 2026, 6:17 PM
Modified
Oct 14, 2026, 1:10 PM