CVE-2026-111215 in pfSense
Summary
by MITRE • 10/15/2026
Netgate pfSense CE through 2.9.0 contains an OS command injection vulnerability that allows authenticated users to execute commands as root by supplying a crafted wireless parent interface name. Attackers with limited Wireless Edit or Interface Assignments privileges can submit values like ath0;<cmd> via interfaces_wireless_edit.php or interfaces_assign.php, which interface_wireless_clone() interpolates unescaped into an ifconfig shell command.
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Analysis
by VulDB Data Team • 10/15/2026
The vulnerability identified in Netgate pfSense Community Edition versions through 2.9.0 represents a critical OS command injection flaw within the network configuration management subsystem. This security defect allows authenticated users with specific, relatively low-privilege roles to escalate their access rights significantly by executing arbitrary system commands as the root user. The core of the issue lies in how the application handles input validation and sanitization for wireless interface configurations. Specifically, when an administrator or authorized user attempts to edit a wireless parent interface via the web-based management console, the backend PHP scripts process the provided interface name without adequate escaping before passing it to system-level network configuration utilities.
The technical mechanism of exploitation centers on the interaction between the web application layer and the underlying operating system shell. When a request is submitted through endpoints such as interfaces_wireless_edit.php or interfaces_assign.php, the data flows into the function interface_wireless_clone(). This function constructs an ifconfig command string to apply network settings. However, it interpolates the user-supplied wireless parent interface name directly into this command without proper sanitization. An attacker can exploit this by injecting shell metacharacters, such as semicolons or pipes, immediately following a valid interface identifier like ath0. For instance, submitting a value formatted as ath0;<cmd> causes the ifconfig utility to execute the injected <cmd> string alongside its intended network configuration task. Because pfSense typically runs these administrative scripts with elevated privileges, often effectively root level depending on sudo configurations and script execution context, this results in arbitrary code execution with the highest possible system permissions.
The operational impact of this vulnerability is severe due to the potential for complete system compromise. An attacker who gains access through valid credentials but holds only limited Wireless Edit or Interface Assignments privileges can bypass these restrictions entirely. By leveraging this command injection vector, they can install backdoors, exfiltrate sensitive data such as SSL certificates and private keys stored on the firewall, modify routing tables to facilitate man-in-the-middle attacks, or pivot into other internal network segments protected by the pfSense appliance. This effectively neutralizes the security boundary provided by role-based access control within the management interface, turning a minor configuration error into a critical breach of system integrity.
Mitigation strategies must address both immediate remediation and long-term secure coding practices. The primary defense is to apply the vendor-provided software updates that patch this specific vulnerability in pfSense CE versions up to 2.9.0 immediately upon release. In environments where updating is not instantly feasible, network segmentation should be enforced to restrict access to the management interface strictly from trusted IP addresses using strong multi-factor authentication. Additionally, input validation must be rigorously implemented at all boundaries where user data interacts with system commands. Developers and administrators should adhere to principles of least privilege and ensure that any string passed to shell execution functions is either escaped properly or replaced with safe API calls that do not invoke a shell interpreter. This aligns with industry standards such as CWE-78, which classifies improper neutralization of special elements used in an OS command, and ATT&CK technique T1059, which covers command and script interpretation attacks commonly leveraged for initial access or privilege escalation on Unix-like systems.