Stored XSS via unsanitized custom CSS
Published Jan 20, 2026 · Updated Jan 20, 2026
Stored XSS in Beckhoff TwinCAT 3 HMI Server before 14.4.267 allows remote authenticated users to inject content through custom CSS. The administrator-only server configuration page accepts arbitrary CUSTOM_CSS content, persists it, and renders it without neutralization on every login and error page. Exploitation requires a malicious administrator; injected browser content can expose or alter data in the security context of users who encounter those pages.
Summary
What happened
Stored XSS in Beckhoff TwinCAT 3 HMI Server before 14.4.267 allows remote authenticated users to inject content through custom CSS. The administrator-only server configuration page accepts arbitrary CUSTOM_CSS content, persists it, and renders it without neutralization on every login and error page. Exploitation requires a malicious administrator; injected browser content can expose or alter data in the security context of users who encounter those pages.
The record
- CVE
- CVE-2025-41768
- Published
- Jan 20, 2026
- Updated
- Jan 20, 2026
- Vendor
- Beckhoff Automation GmbH & Co. KG
- Product
- TwinCAT 3 HMI Server
- Classifications
- CWE-79, T1059.007
- Attack vector
- network
- Privileges
- admin
Timeline
How it unfolded
- Jan 20, 2026CVE publishedPublication date reported by the CVE source.
- Jan 20, 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=0.0.0 <14.4.267
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
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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