XSS in Opnsense
CVE-2019-25377
OPNsense 19.1 contains a reflected cross-site scripting vulnerability in the system_advanced_sysctl.php endpoint that allows attackers to inject malicious scripts via the value parameter. Attackers can craft POST requests with script payloads in the value parameter to execute JavaScript in the context of authenticated user sessions.
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: 0.003 (15.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 15th percentile — 15.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.000
Affected products
- Opnsense — versions 19.1
Weakness classification (CWE)
References
- www.exploit-db.com/exploits/46351 (Exploit, VDB Entry, Third Party Advisory, exploit)
- opnsense.org (Product, product)
- forum.opnsense.org/index.php (Release Notes, patch)
- www.vulncheck.com/advisories/opnsense-reflected-xss-via-systemadvancedsysctlphp (Broken Link, third-party-advisory)
Frequently asked questions
- What is CVE-2019-25377?
- CVE-2019-25377 is a medium-severity vulnerability in Opnsense, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-02-15.
- How severe is CVE-2019-25377?
- Medium severity. CVSS v3 base score is 5.4 out of 10.