OPNsense 19.1 Reflected XSS via monit interface
Published Feb 15, 2026
5.1
MEDIUMCVSS 4.0
EPSS 0.37%
Description
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.
Affected products
-
- Version 19.1StatusaffectedConstraints-
- Version
No data.
No Red Hat product state for this CVE.
No package ranges for this CVE.
Remediation
Vendor solution
OPNsense 19.1.1 released
Metrics
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
1 other source (NVD) ▾
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
No CVSS v3.0 score for this CVE.
No CVSS v2.0 score for this CVE.
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
PoCAutomatable
YesTechnical Impact
PartialDecision
n/aAssessed Feb 17, 2026 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 2, 2026.
Score over time
Feb–Oct 2026- EPSS v4
- EPSS v5
Percentile over time
- EPSS v4
- EPSS v5
Table of values (3 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 2, 2026 | 0.37% (0.00374) | 28.99th | v5 (v2026.06.15) |
| Jun 15, 2026 | 0.36% (0.00360) | 27.60th | v5 (v2026.06.15) |
| Feb 16, 2026 | 0.10% (0.00101) | 27.99th | v4 (v2025.03.14) |
References (4)
- https://forum.opnsense.org/index.php?topic=11469.0 patchRelease Notes
- https://opnsense.org product
- https://www.exploit-db.com/exploits/46351 exploitThird Party AdvisoryVDB Entry
- https://www.vulncheck.com/advisories/opnsense-reflected-xss-via-monit-interface third-party-advisoryThird Party Advisory
| Link | Providers | Tags |
|---|---|---|
| https://forum.opnsense.org/index.php?topic=11469.0 | patchRelease Notes | |
| https://opnsense.org | product | |
| https://www.exploit-db.com/exploits/46351 | exploitThird Party AdvisoryVDB Entry | |
| https://www.vulncheck.com/advisories/opnsense-reflected-xss-via-monit-interface | third-party-advisoryThird Party Advisory |
Change history (0)
No recorded changes yet.