Authenticated script execution via unescaped sysctl value
Published Feb 15, 2026 · Updated Feb 15, 2026
Reflected XSS in OPNsense 19.1 allows remote authenticated users to execute JavaScript through the sysctl value parameter. The system_advanced_sysctl.php editor returns the POSTed value in an HTML response without context-appropriate output escaping. Exploitation requires valid WebGUI access and victim interaction; the script executes in the victim's session and can read or modify interface data available to that session.
Summary
What happened
Reflected XSS in OPNsense 19.1 allows remote authenticated users to execute JavaScript through the sysctl value parameter. The system_advanced_sysctl.php editor returns the POSTed value in an HTML response without context-appropriate output escaping. Exploitation requires valid WebGUI access and victim interaction; the script executes in the victim's session and can read or modify interface data available to that session.
The record
- CVE
- CVE-2019-25377
- Published
- Feb 15, 2026
- Updated
- Feb 15, 2026
- Vendor
- Deciso B.V.
- Product
- OPNsense
- Classifications
- CWE-79, T1203
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 15, 2026CVE publishedPublication date reported by the CVE source.
- Feb 15, 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=19.1
What conditions does exploitation require?
What is affected?
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
- OPNsense 19.1 Cross-Site Scripting proof of conceptproof of concept · unverified
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Technologies
Your stack
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Your stack
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