CVE-2025-7081: Belkin F9K1122 Firmware RCE Vulnerability

CVE-2025-7081 Overview

CVE-2025-7081 is an operating system (OS) command injection vulnerability in the Belkin F9K1122 wireless router running firmware version 1.00.33. The flaw exists in the formSetWanStatic function within /goform/formSetWanStatic, part of the device's webs component. Attacker-controlled values for m_wan_ipaddr, m_wan_netmask, m_wan_gateway, m_wan_staticdns1, and m_wan_staticdns2 are passed directly to a shell context without sanitization. An authenticated remote attacker can inject arbitrary shell commands that execute on the router. The vendor was contacted but did not respond, and the exploit details are public. The vulnerability is tracked under CWE-77.

Critical Impact
Authenticated remote attackers can execute arbitrary OS commands on affected Belkin F9K1122 routers, enabling full device takeover, traffic interception, and pivoting into adjacent networks.

Affected Products

Belkin F9K1122 router (hardware)
Belkin F9K1122 firmware version 1.00.33
The webs HTTP service handling /goform/formSetWanStatic

Discovery Timeline

2025-07-06 - CVE-2025-7081 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-7081

Vulnerability Analysis

The vulnerability resides in the formSetWanStatic handler exposed through the router's embedded webs HTTP server. The handler is invoked when an administrator submits static WAN configuration through the device's management interface. The five WAN-related parameters are intended to carry IP addresses, netmasks, and DNS server values, but the handler concatenates them into shell command strings without input validation or escaping.

An attacker with access to the management interface, whether on the LAN or via an exposed administrative port, can submit a crafted POST request that breaks out of the expected argument context using shell metacharacters. Commands execute under the privileges of the webs process, which on consumer-grade routers typically runs as root. The result is full command execution on the device. Because the vendor has not issued a fix and did not respond to coordinated disclosure, affected devices remain exposed.

Root Cause

The root cause is improper neutralization of special elements used in an OS command [CWE-77]. The formSetWanStatic function trusts user-supplied parameters and passes them into a system shell invocation, likely through a system(), popen(), or exec-family call used to configure the underlying network stack with utilities such as ifconfig or route.

Attack Vector

The attack is launched remotely over the network against the router's HTTP administration service. The CVSS vector indicates low-privilege authentication is required, meaning an attacker needs valid credentials or must reach the interface in a context where default or weak credentials are in use. After authenticating, the attacker submits a POST to /goform/formSetWanStatic with shell metacharacters embedded in the WAN parameters. The injected command runs immediately on the router. Technical details and a proof-of-concept are documented in the public GitHub Vulnerability Documentation and the VulDB #314995 Entry.

// Vulnerability mechanism (described in prose; no verified exploit code reproduced)
// A POST to /goform/formSetWanStatic with a crafted m_wan_ipaddr value
// containing shell metacharacters (e.g., backticks, semicolons, or $())
// is concatenated into a system() call and executed by the webs process.

Detection Methods for CVE-2025-7081

Indicators of Compromise

HTTP POST requests to /goform/formSetWanStatic containing shell metacharacters such as ;, |, &, backticks, or $() inside WAN parameters.
Unexpected outbound connections initiated by the router to attacker-controlled infrastructure following WAN configuration changes.
New or modified processes on the device beyond the standard Belkin webs, httpd, and networking daemons.
Configuration changes to DNS, routing, or firewall rules that were not performed by an administrator.

Detection Strategies

Inspect web server and reverse proxy logs in front of router management interfaces for POSTs to /goform/formSetWanStatic carrying non-IP characters in the five vulnerable parameters.
Use network intrusion detection signatures that flag command injection metacharacters in HTTP request bodies destined for embedded device management endpoints.
Monitor for outbound traffic from router management VLANs to non-standard destinations, including unusual DNS, ICMP, or HTTP callbacks.

Monitoring Recommendations

Centralize syslog from network edge devices and alert on configuration changes outside maintenance windows.
Track EPSS movement for CVE-2025-7081, which is currently elevated at roughly 15% with a 96th percentile ranking, indicating relatively high exploitation likelihood compared with peers.
Maintain an asset inventory of consumer-grade Belkin equipment in corporate and remote-worker environments and audit those segments for management interface exposure.

How to Mitigate CVE-2025-7081

Immediate Actions Required

Remove the Belkin F9K1122 from any role that exposes its management interface to untrusted networks, including direct WAN exposure.
Restrict administrative access to a dedicated management VLAN and enforce strong, unique credentials to raise the bar for the required low-privilege authentication.
Inventory all F9K1122 devices running firmware 1.00.33 and prioritize replacement with a currently supported router, since the vendor has not responded to disclosure.

Patch Information

No vendor patch is available. According to the disclosure, Belkin was contacted before public release and did not respond. Organizations should treat the F9K1122 on firmware 1.00.33 as end-of-support for security purposes and plan device replacement. Monitor the VulDB advisory for any future vendor update.

Workarounds

Disable remote (WAN-side) administration on the device and limit LAN-side administration to a single trusted host.
Place the router behind an upstream firewall that blocks inbound access to its HTTP management port from untrusted segments.
Rotate administrative credentials and disable any unused services such as UPnP or remote management protocols.
Segment the router from sensitive internal assets so that command execution on the device does not provide a pivot point into production networks.

bash

# Example: restrict management access on an upstream firewall (iptables)
# Allow only a trusted management host to reach the router's web UI
iptables -A FORWARD -s 192.0.2.10/32 -d 192.168.1.1 -p tcp --dport 80 -j ACCEPT
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 443 -j DROP