Security readout for executives and security teams
Plain-English summary
OPNsense 19.1 has a reflected cross-site scripting issue in an administrative endpoint. An attacker with access to the interface and a logged-in user’s interaction could run JavaScript in that user’s browser session. Business risk is mainly compromise of administrator actions or data in the management UI, not direct firewall takeover by itself.
Executive priority
Treat as a timely hygiene fix for firewall management systems. Prioritize if OPNsense 19.1 is still deployed, especially if the admin UI is broadly reachable. This is not marked as actively exploited, but public exploit information raises remediation urgency.
Technical view
CVE-2019-25377 is CWE-79 in OPNsense 19.1, affecting system_advanced_sysctl.php through the value parameter. CVSS 3.1 is 5.4: network reachable, low complexity, low privileges required, user interaction required, changed scope, low confidentiality and integrity impact, no availability impact.
Likely exposure
Exposure is most likely where OPNsense 19.1 management interfaces are reachable by users beyond a tightly controlled admin network. The issue requires authenticated context and user interaction, reducing broad internet-scale risk but increasing concern for phishing or insider scenarios.
Exploitation context
The source bundle includes an ExploitDB reference, indicating public exploit information exists. CISA KEV status is false, and the provided sources do not state active exploitation in the wild.
Researcher notes
Evidence identifies OPNsense 19.1 and the value parameter in system_advanced_sysctl.php. The issue is reflected XSS with PR:L and UI:R. The bundle points to OPNsense 19.1.1 as patch-related, but organizations should verify the exact fixed version from vendor release guidance.
Mitigation direction
- Identify any OPNsense 19.1 deployments.
- Apply OPNsense vendor update guidance, including the 19.1.1 release path where applicable.
- Restrict management UI access to trusted administrative networks.
- Require strong authentication for OPNsense administrators.
- Train administrators to avoid unsolicited links while logged in.
Validation and detection
- Confirm OPNsense version and whether 19.1 is present.
- Review access controls for the management interface.
- Check logs for unusual requests to system_advanced_sysctl.php.
- Verify remediation against OPNsense release notes or current vendor guidance.
- Confirm administrators use separate, hardened admin workstations where possible.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2019-25377 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.4 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N2.32.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.4MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- ExploitDB-46351CVE reference · exploit
- OPNsense Official WebsiteCVE reference · product
- OPNsense 19.1.1 Release AnnouncementCVE reference · patch
- VulnCheck Advisory: OPNsense 19.1 Reflected XSS via system_advanced_sysctl.phpCVE reference · third-party-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.