Johnson Controls Metasys
View CSAF Summary Successful exploitation of this vulnerability could allow a low-privilege user or attacker to inject a persistent malicious payload via a crafted URL that executes in the context of other users' sessions, including administrators, potentially leading to session hijacking and unauthorized access. The following versions of Johnson Controls Metasys are affected: Metasys 12 vers:all/* (CVE-2026-34491) Metasys 13 vers:all/* (CVE-2026-34491) Metasys 14 Metasys 15 CVSS Vendor Equipment Vulnerabilities v3 8 Johnson Controls Inc Johnson Controls Metasys Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') 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-2026-34491 A low-privilege user can inject a malicious XSS payload into the Metasys UI via a crafted URL.
Reported by 1 outlet — CISA. See all sources ↓
View CSAF Summary Successful exploitation of this vulnerability could allow a low-privilege user or attacker to inject a persistent malicious payload via a crafted URL that executes in the context of other users' sessions, including administrators, potentially leading to session hijacking and unauthorized access. The following versions of Johnson Controls Metasys are affected: Metasys 12 vers:all/* (CVE-2026-34491) Metasys 13 vers:all/* (CVE-2026-34491) Metasys 14 Metasys 15 CVSS Vendor Equipment Vulnerabilities v3 8 Johnson Controls Inc Johnson Controls Metasys Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') 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-2026-34491 A low-privilege user can inject a malicious XSS payload into the Metasys UI via a crafted URL. The payload persists across logins and executes in the browser context of other users, including administrators. View CVE Details Affected Products Johnson Controls Metasys Vendor:Johnson Controls Inc Product Version:Johnson Controls Inc Metasys 12: vers:all/*, Johnson Controls Inc Metasys 13: vers:all/*, Johnson Controls Inc Metasys 14: <v14.1.5, Johnson Controls Inc Metasys 15: <v15.0.1 Product Status:known_affected Remediations MitigationJohnson Controls recommends the following actions: MitigationUser are recommended to apply the latest available patches for affected Metasys versions MitigationMetasys 16.0: Not impacted, fixed prior to release Vendor fixMetasys 15.0: Patch released 2026-03-25 Vendor fixMetasys 14.1.5: Forecast release 2026-07-15 Vendor fixMetasys 13: End of support, update to later version Vendor fixMetasys 12: End of support, update to later version MitigationMetasys 11 & prior: Not affected (vulnerability introduced at version 12) MitigationTo help reduce the risk of exploitation, we suggest considering the following defensive measures: MitigationUpgrade to Metasys version 16.0 or apply the latest available patch for your version (15.0.1 or 14.1.5 when available) MitigationRestrict network access to the Metasys UI to trusted networks and users only; do not expose the interface directly to the internet MitigationImplement network segmentation to isolate building automation systems from the corporate IT network MitigationEnforce least-privilege access controls – limit user accounts to the minimum permissions necessary MitigationImplement Content Security Policy (CSP) headers and other HTTP security headers where possible at the network/proxy level MitigationMonitor for suspicious URL patterns and unexpected script execution in Metasys UI access logs MitigationUse a web application firewall (WAF) in front of the Metasys UI to detect and block common XSS payloads MitigationEducate users to avoid clicking on untrusted or unexpected links that target the Metasys UI MitigationFor more detailed mitigation instructions, please see Johnson Controls Product Security Advisory JCI-PSA-2026-11 at the following location: Security Advisories.
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Why it matters
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- What's the story?
- View CSAF Summary Successful exploitation of this vulnerability could allow a low-privilege user or attacker to inject a persistent malicious payload via a crafted URL that executes in the context of other users' sessions, including administrators, potentially leading to session hijacking and unauthorized access. The following versions of Johnson Controls Metasys are affected: Metasys 12 vers:all/* (CVE-2026-34491) Metasys 13 vers:all/* (CVE-2026-34491) Metasys 14 Metasys 15 CVSS Vendor Equipment Vulnerabilities v3 8 Johnson Controls Inc Johnson Controls Metasys Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') 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-2026-34491 A low-privilege user can inject a malicious XSS payload into the Metasys UI via a crafted URL.
- How widely is it covered?
- 1 outlet, average source rating 9.0/10.
- When was it last updated?
- 1h ago.
How outlets are framing the same story
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- Coverage card1 outlet1CoverageScouting report
Johnson Controls Metasys
Sources1TypeCoverageCISA