CVE-2026-57154

What it is

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.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account. High risk of data tampering, service disruption.

Exploit odds

0.5% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-06-24 01:45 UTC ReservedThe CVE id was reserved by its CNA
2. 2026-11-03 19:18 UTC PublishedDisclosed publicly on CVE.org and NVD
3. 2026-11-07 04:17 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.5% in the next 30 days (EPSS).
• Severity: 8.1 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-11-03 19:18 UTC

Last modified

2026-11-07 04:17 UTC

Exploit probability

0.5% · EPSS, next 30 days

Weakness

CWE-74

Record status

Received

Attack profile CVSS 3.1 · 8.1

Attack vector

Network

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-57154.md and follow it. Check whether this project is affected by CVE-2026-57154. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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