XSS in Netgate Pfsense Ce
CVE-2026-56126
pfSense Plus before 26.07 and CE before 2.9.0 allow authenticated users with the Status: Monitoring privilege to inject arbitrary JavaScript via graph configuration parameters in /status_monitoring.php. Multiple POST parameters including graph-left, graph-right, time-period, resolution, start-date, end-date, start-time, end-time, graph-type, invert, and refresh-interval are concatenated and written to the global pfSense XML configuration without sanitization, then echoed unsanitized into a JavaScript string context on page render. Because the setting is stored in the global configuration, the payload executes in the browser of every user who visits the Status: Monitoring page.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.011 (63.7th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 64th percentile — 63.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.011 · change: +0.007
Affected products
Weakness classification (CWE)
References
- Vendor Advisory (vendor-advisory, patch)
- CE Release Notes (release-notes)
- Plus Release Notes (release-notes)
- www.vulncheck.com/advisories/pfsense-plus-ce-stored-xss-via-status-monitoring-p… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-56126?
- CVE-2026-56126 is a medium-severity vulnerability in Netgate Pfsense Ce, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-09-03.
- How severe is CVE-2026-56126?
- Medium severity. CVSS v3 base score is 5.4 out of 10.