Analyst readout for executives and security teams
Plain-English summary
OPNsense 19.1 has a reflected cross-site scripting flaw in an IPsec VPN settings page. An attacker could trick a user into submitting malicious content that runs script in that user’s browser. This is not described as server takeover, but it can affect browser-session confidentiality and integrity.
Executive priority
Treat this as a moderate-risk hygiene item. It is most urgent for organizations still running old OPNsense 19.1 systems with reachable administration interfaces. The main business concern is compromise of administrator browser sessions, not direct firewall code execution based on current sources.
Technical view
CVE-2019-25374 is CWE-79 reflected XSS in vpn_ipsec_settings.php via the passthrough_networks parameter. The published CVSS 3.1 score is 6.1, with network attack vector, low complexity, no privileges required, and user interaction required. Scope is changed with low confidentiality and integrity impact.
Likely exposure
Exposure appears limited to OPNsense 19.1 deployments, especially where administrators or users can reach the affected VPN/IPsec settings workflow. Systems not running OPNsense 19.1 are not identified as affected in the provided sources.
Exploitation context
A public Exploit-DB entry is referenced, so defenders should assume exploit knowledge is available. The source bundle does not indicate CISA KEV listing or confirmed active exploitation. Successful abuse requires user interaction and impacts the user’s browser context.
Researcher notes
Evidence identifies reflected XSS in passthrough_networks on vpn_ipsec_settings.php. The bundle includes an Exploit-DB reference and a 19.1.1 release announcement tagged as patch, but no detailed vendor fix text is provided here. Avoid assuming broader version impact without vendor confirmation.
Mitigation direction
- Identify any OPNsense 19.1 systems in production or lab environments.
- Review the OPNsense 19.1.1 release announcement and vendor guidance for upgrade direction.
- Restrict administrative access to trusted networks and users where possible.
- Prioritize retiring unsupported or legacy firewall versions.
Validation and detection
- Check OPNsense version information for 19.1 installations.
- Review access paths to the VPN/IPsec settings interface.
- Confirm whether OPNsense 19.1.1 or later vendor-recommended updates are applied.
- Monitor administrative browser sessions for unexpected script-related alerts or anomalies.
Public sources used
Based on public source material and reviewed before publication.
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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2019-25374 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
- 6.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/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:N/UI:R/S:C/C:L/I:L/A:N2.82.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.1MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/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 vpn_ipsec_settings.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.