Incorrect access control in the WebUI in OPNsense before version 19.1.8, and pfsense before 2.4.4-p3 allows remote authenticated users to escalate privileges to administrator via a specially crafted request.
An authenticated command injection vulnerability exists in status_interfaces.php via dhcp_relinquish_lease() in pfSense before 2.4.4 due to its passing user input from the $_POST parameters "ifdescr" and "ipv" to a shell without escaping the contents of the variables. This allows an authenticated WebGUI user with privileges for the affected page to execute commands in the context of the root user when submitting a request to relinquish a DHCP lease for an interface which is configured to obtain its address via DHCP.
pfSense versions 2.4.1 and lower are vulnerable to clickjacking attacks in the CSRF error page resulting in privileged execution of arbitrary code, because the error detection occurs before an X-Frame-Options header is set. This is fixed in 2.4.2-RELEASE. OPNsense, a 2015 fork of pfSense, was not vulnerable since version 16.1.16 released on June 06, 2016. The unprotected web form was removed from the code during an internal security audit under "possibly insecure" suspicions.