CVE-2026-57154
HighCVSS 8.1Exploitation Probability (EPSS)
Low risk40th percentile - higher than 40% of all known CVEs
Summary
In OPNsense 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. This spans Dnsmasq, OpenVPN, DHCPv6, Unbound, IPsec, NTP, PPP/MPD, Monit, firewall, sudo, WebGUI, and System General configuration; line injection through the Monit mail password into /usr/local/etc/monitrc demonstrated root command execution.
Risk Assessment
Potential RBAC boundary crossing, altered service behavior, service-side file creation, and denial of service, and in the Monit case root command execution. Requires authenticated access with delegated privileges.
Recommendation
Update OPNsense to version 26.1.11 or 26.4.1p1 or later and review delegated permissions and generated configuration files for injected lines.
Other vulnerabilities in OPNsense
See all- CVE-2026-57155Critical
In OPNsense prior to 26.1.11, the Firewall Alias GeoIP importer uses an unvalidated CSV country_code value to construct output filenames, allowing path traversal. A user with Firewall Alias Edit privilege can supply a crafted archive and write attacker-controlled content as root, then leverage cron to execute commands as root.
- CVE-2026-53581Critical
OPNsense is a FreeBSD based firewall and routing platform. Prior to version 26.1.9 of opnsense/core and version 26.4_20 of BE/opnsense/core, a path traversal vulnerability in the NTP configuration module allows an attacker to overwrite arbitrary files on the system as the root user. By manipulating the GPS or PPS serial port parameter, an attacker with access to the NTP configuration can escape the intended directory and write user-controlled data to any file.
- CVE-2026-45158Critical
OPNsense is a FreeBSD based firewall and routing platform. Prior to version 26.1.8, unsanitized user input was passed to the DHCP configuration, allowing remote code execution as root on the underlying operating system.
- CVE-2026-44193Critical
OPNsense is a FreeBSD based firewall and routing platform. In versions prior to 26.1.7, the XMLRPC method opnsense.restore_config_section fails to sanitize user supplied input, leading to Remote Code Execution.
- CVE-2023-39004Critical
Insecure permissions in the configuration directory (/conf/) of OPNsense Community Edition before 23.7 and Business Edition before 23.4.2 allow attackers to access sensitive information (e.g., hashed root password) which could lead to privilege escalation.
- CVE-2026-119560Medium
OPNsense core through 26.7.8 contains a configuration injection vulnerability that allows authenticated users to append ntpd.conf directives by embedding newlines in the fudge and refid fields. Attackers holding the page-services-ntp-gps or PPS privilege can submit CR/LF characters via services_ntpd_gps.php or services_ntpd_pps.php to inject directives loaded by ntpd running as root.
- CVE-2026-119425Medium
OPNsense core 26.1.6 through 26.7.7 contains an authentication bypass vulnerability in the captive portal roaming feature that lets unauthenticated attackers hijack authorized client sessions by spoofing unauthenticated MAC-to-IP observations. Attackers on the same Layer-2 segment can send forged gratuitous ARP replies binding their IP to a victim's MAC, gaining portal access with traffic attributed to the victim.
- CVE-2026-119424Medium
OPNsense core before 26.7.8 contains a configuration line injection vulnerability that allows authenticated users with wireless-edit privilege to inject directives by embedding CR/LF characters in WPA fields. Attackers can place newlines in wpa.identity, wpa.passphrase, or RADIUS shared secrets to append arbitrary wpa_supplicant or hostapd directives loaded by root-run daemons.
- CVE-2026-119423Medium
OPNsense core before 26.7.8 contains a log injection vulnerability that allows unauthenticated attackers to plant victim IP addresses in the lockout_handler by submitting crafted WebGUI login usernames. Attackers can submit usernames like 'Invalid user <victim-ip>' repeatedly to add the victim to the sshlockout table, blocking SSH and WebGUI access and killing its pf states.
- CVE-2026-119409High
OPNsense before 26.7.8 contains a command injection vulnerability that allows authenticated users with the System: Firmware privilege to execute commands as root by storing a malicious firmware mirror URL. Attackers can submit shell metacharacters through POST /api/core/firmware/set that opnsense-update evaluates with eval, and can also disable package signature verification through sed injection.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS

