Arbitrary JavaScript execution via unencoded captive username
Published Sep 4, 2026 · Updated Sep 4, 2026
Stored XSS in Netgate pfSense Plus 26.03 and earlier and pfSense CE 2.8.1 and earlier allows remote attackers to run JavaScript. The unauthenticated Captive Portal accepts an auth_user username without validation, stores it, and the dashboard widget renders it without encoding. Exploitation requires a local-network client on an interface whose Captive Portal uses authentication type None and an administrator viewing the widget; the script can expose the administrator's session cookie or other session data.
Summary
What happened
Stored XSS in Netgate pfSense Plus 26.03 and earlier and pfSense CE 2.8.1 and earlier allows remote attackers to run JavaScript. The unauthenticated Captive Portal accepts an auth_user username without validation, stores it, and the dashboard widget renders it without encoding. Exploitation requires a local-network client on an interface whose Captive Portal uses authentication type None and an administrator viewing the widget; the script can expose the administrator's session cookie or other session data.
The record
- CVE
- CVE-2026-78849
- Published
- Sep 4, 2026
- Updated
- Sep 4, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- T1059.007
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 4, 2026CVE publishedPublication date reported by the CVE source.
- Sep 4, 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?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
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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
- poc-xss-cp-widget.pyproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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