XSS in Opnsense
CVE-2019-25375
OPNsense 19.1 contains a reflected cross-site scripting vulnerability that allows unauthenticated attackers to inject malicious scripts by submitting crafted input to the mailserver parameter. Attackers can send POST requests to the monit interface with JavaScript payloads in the mailserver parameter to execute arbitrary code in users' browsers.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.004 (28.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 28.8% 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: 0.004 · 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-monit-interface (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2019-25375?
- CVE-2019-25375 is a medium-severity vulnerability in Opnsense, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-02-15.
- How severe is CVE-2019-25375?
- Medium severity. CVSS v3 base score is 6.1 out of 10.