CVE-2026-34491

Johnson Controls Inc Metasys 12 — vulnerability CVE-2026-34491

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.

CVSS 6.1No patch available

This record: live connection— last retrieved: 8 November 2026 at 18:29.

Vendor

Johnson Controls Inc.

Product

Metasys 12

up to version vers:all/*

Published

24 August 2026

Last modified

14 October 2026

Original source information

Taken directly from NVD, CISA or the vendor — sometimes in English, unchanged from the source.

Technical description

CVSS 4.0 — vector details

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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack vector

NETWORK

Privileges required

LOW

User interaction

REQUIRED

Confidentiality

High

Integrity

High

Availability

High

EPSS — Exploit Prediction Scoring System

Probability of exploitation within 30 days

0.4%

Percentile

34e

Source: FIRST.org, updated on 8 November 2026.

Patch information

Johnson Controls recommends the following actions:

IACS Radar assessment

Our own interpretation and context for the source data above.

IACS Radar assessment

Our own interpretation and context for this vulnerability — not an official source.

IACS Radar priority score

35/ 100

Based on CVSS 6.1, EPSS 0.4%, industrial relevance 40/100.

Combines CVSS, EPSS, KEV status, industrial relevance and exposure relevance — a complement to, not a replacement for, the individual scores below and above.

Conditions for exploitation

•Network access to the affected device or segment is required.
•Limited user privileges are required.
•User interaction (for example opening a file) is required.

Operational impact & energy relevance

Possible loss of visibility of or control over the process upon successful exploitation.

No strong energy-sector-specific signals recognised; general OT/ICS relevance.

Recommended defensive measures

•Apply the latest firmware or software update and validate its integrity.
•Restrict network access to the affected device to a dedicated OT management segment.
•Implement network segmentation in line with zones and conduits (IEC 62443-3-2).
•Monitor for abnormal protocol traffic using an OT-aware detection system.

Industrial relevance score

40/ 100

• Mentioned in an official CISA ICS advisory, which confirms direct relevance to industrial control systems.
• Sector indication recognised in the description: energieopwekking.

Classification is provisional; manual verification by an OT security analyst is recommended.

Classified by IACS Radar-analysepijplijn (geautomatiseerd) on 8 November 2026.

IEC 62443 mapping

IEC 62443-4-1FR3 · Systeemintegriteit

Automatic IACS Radar assessment based on the reported CWE weakness classification; not an official certification statement.

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