Session hijacking via persistent crafted-URL script injection
Published Aug 24, 2026 · Updated Aug 25, 2026
Stored cross-site scripting in Johnson Controls Metasys 14 before 14.1.5 and 15 before 15.0.1 allows remote authenticated users to hijack sessions. The Metasys UI stores a malicious payload supplied through a crafted URL and later executes it in other users' browser contexts. A low-privilege account and a later victim login are required; administrator exposure permits session hijacking and unauthorized access.
Summary
What happened
Stored cross-site scripting in Johnson Controls Metasys 14 before 14.1.5 and 15 before 15.0.1 allows remote authenticated users to hijack sessions. The Metasys UI stores a malicious payload supplied through a crafted URL and later executes it in other users' browser contexts. A low-privilege account and a later victim login are required; administrator exposure permits session hijacking and unauthorized access.
The record
- CVE
- CVE-2026-34491
- Published
- Aug 24, 2026
- Updated
- Aug 25, 2026
- Vendor
- Johnson Controls
- Product
- Metasys
- Classifications
- CWE-79, T1539
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 24, 2026CVE publishedPublication date reported by the CVE source.
- Aug 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <14.1.5
- Affected versionversion=0 <15.0.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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