CVSS 3.1
8.1 highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:HCVE-2026-57154
High (8.1). EPSS 0.5% estimated probability of exploitation activity in the next 30 days.
OPNsense is a FreeBSD based firewall and routing platform. Prior to 26.1.11 and 26.4.1p1, authenticated Web UI or API users with delegated access to affected settings can submit CR or LF characters in fields expected to contain one line, causing generated privileged service configuration files to contain additional attacker-controlled directives or policy lines. The confirmed Dnsmasq path includes dhcp_boot.filename, dhcp_boot.servername, dhcp_boot.address, and dhcp_options.value, which are rendered into /usr/local/etc/dnsmasq.conf; access through page-services-dnsforwarder covers api/dnsmasq/*. Related affected fields span OpenVPN, DHCPv6, Unbound, IPsec, NTP, PPP or MPD, Monit, firewall, sudo, WebGUI, and System General configuration. Applying or restarting the affected service can alter behavior beyond the delegated setting, create service-side files, cross RBAC boundaries, or cause denial of service. Line injection through Monit mail password and adjacent Monit text fields into /usr/local/etc/monitrc demonstrated root command execution. Arbitrary shell command execution was not confirmed for the Dnsmasq path. This issue is fixed in versions 26.1.11 and 26.4.1p1.
Severity
- EPSS
- 0.5% estimated probability of exploitation activity in the next 30 days; 40th percentile. Scored 2026-11-04. A forecast for this CVE across the internet, not for your own systems.
- CWEs
- CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection)
CWE-93 Improper Neutralization of CRLF Sequences (CRLF Injection) - OWASP Top 10
- A05:2025 Injection
- Published
- Record from
- the NVD, synced
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Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| opnsense core | < 26.1.11 |
Attack patterns (CAPEC)
- CAPEC-15 Command Delimiters Likelihood: High · Severity: High
- CAPEC-81 Web Server Logs Tampering Likelihood: Medium · Severity: High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits. More on the page of CWE-74 (37).