Security readout for executives and security teams
Plain-English summary
OPNsense 19.1 has a stored cross-site scripting flaw in an advanced system settings page. A lower-privileged authenticated user could save malicious script content that later runs in another authenticated user’s browser. Business risk is mainly compromise of firewall administration sessions or unauthorized changes through the management interface.
Executive priority
Treat as a medium-priority firewall administration risk. Prioritize remediation if OPNsense 19.1 is still in use, especially where the management interface is reachable by many users or from untrusted networks.
Technical view
CVE-2019-25369 is CWE-79 stored XSS in OPNsense 19.1, affecting system_advanced_sysctl.php via the tunable parameter. The CVSS 3.1 score is 6.4. The vulnerability requires authenticated access, is network-reachable, and can impact confidentiality and integrity across the browser security boundary.
Likely exposure
Exposure is limited to OPNsense 19.1 systems where attackers can authenticate to, or otherwise submit data through, the management interface. Internet-exposed administration portals increase practical risk. Systems not running OPNsense 19.1 are not identified as affected in the provided sources.
Exploitation context
A public ExploitDB entry exists, so proof-of-concept information is available. The provided sources do not show CISA KEV listing or confirmed active exploitation. The issue is most relevant to environments with shared firewall administration, weak admin access controls, or exposed management interfaces.
Researcher notes
The source bundle attributes the flaw to persistent script injection through the tunable parameter on system_advanced_sysctl.php. Public exploit material exists, but active exploitation is not evidenced here. Confirm exact remediation details against OPNsense release notes before making vulnerability-status determinations.
Mitigation direction
- Upgrade affected OPNsense 19.1 systems to 19.1.1 or a later vendor-supported release.
- Restrict OPNsense management access to trusted administrator networks.
- Review and remove suspicious tunable values from advanced system settings.
- Follow current OPNsense vendor guidance for any additional fixes or hardening.
Validation and detection
- Inventory OPNsense firewalls and identify any running version 19.1.
- Confirm whether the management interface is exposed beyond trusted networks.
- Review sysctl tunable entries for unexpected script-like content.
- Check administrative logs for unusual POST activity to system_advanced_sysctl.php.
- Verify upgrade status against the OPNsense 19.1.1 release guidance.
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-2019-25369 mapping review
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Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.4 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/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:N/S:C/C:L/I:L/A:N3.12.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.4MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/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 Stored 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.