CVE-2025-9149 Overview
A command injection vulnerability has been identified in the Wavlink WL-NU516U1 network adapter with firmware version M16U1_V240425. This vulnerability affects the function sub_4032E4 within the /cgi-bin/wireless.cgi file. An attacker can manipulate the Guest_ssid argument to inject arbitrary system commands, allowing unauthorized command execution on the affected device. The vulnerability can be exploited remotely over the network, and proof-of-concept exploit details have been publicly disclosed.
Critical Impact
Remote attackers with low-level privileges can execute arbitrary commands on the vulnerable Wavlink device by injecting malicious input through the Guest_ssid parameter, potentially leading to full device compromise.
Affected Products
- Wavlink WL-NU516U1 Firmware version M16U1_V240425
- Wavlink WL-NU516U1 Hardware
Discovery Timeline
- August 19, 2025 - CVE-2025-9149 published to NVD
- October 6, 2025 - Last updated in NVD database
Technical Details for CVE-2025-9149
Vulnerability Analysis
This command injection vulnerability (CWE-77) stems from improper neutralization of special elements used in a command (CWE-74). The vulnerable function sub_4032E4 in /cgi-bin/wireless.cgi fails to properly sanitize user-supplied input in the Guest_ssid parameter before passing it to system command execution functions.
When a user submits a request to configure the guest wireless network SSID, the firmware directly incorporates the user-supplied value into a system command without adequate input validation. This allows attackers to append arbitrary shell commands using command separators such as semicolons, pipes, or backticks.
The vulnerability requires network access and low-level authentication, making it exploitable by any user with access to the device's web interface. Successful exploitation can result in limited confidentiality, integrity, and availability impacts on the affected device.
Root Cause
The root cause is insufficient input validation and sanitization in the CGI handler for wireless configuration. The sub_4032E4 function constructs shell commands by directly concatenating user input from the Guest_ssid parameter without escaping shell metacharacters or implementing proper input validation. This classic command injection pattern allows attackers to break out of the intended command context and execute arbitrary commands with the privileges of the web server process.
Attack Vector
The attack is carried out remotely over the network by submitting a crafted HTTP request to the /cgi-bin/wireless.cgi endpoint. An attacker with authenticated access to the device's management interface can inject shell commands through the Guest_ssid parameter.
The exploitation mechanism involves:
- Authenticating to the Wavlink device's web management interface
- Navigating to the wireless guest network configuration page
- Submitting a malicious Guest_ssid value containing command injection payloads
- The injected commands execute with the privileges of the CGI process
Technical details and proof-of-concept information have been documented in the GitHub PoC Repository. Additional vulnerability details are available at VulDB #320528.
Detection Methods for CVE-2025-9149
Indicators of Compromise
- Unusual HTTP requests to /cgi-bin/wireless.cgi containing shell metacharacters (;, |, $(), backticks) in the Guest_ssid parameter
- Unexpected processes spawned by the web server process on the Wavlink device
- Unauthorized modifications to device configuration or firmware
- Outbound network connections from the device to suspicious external hosts
Detection Strategies
- Monitor and log all HTTP requests to /cgi-bin/wireless.cgi endpoints on Wavlink devices for injection patterns
- Implement network intrusion detection rules to identify command injection attempts containing shell metacharacters
- Deploy web application firewall (WAF) rules to block requests with suspicious payloads in wireless configuration parameters
- Review device access logs for authentication anomalies and configuration changes
Monitoring Recommendations
- Enable comprehensive logging on network segments where Wavlink devices are deployed
- Monitor for unexpected outbound connections or DNS queries from IoT devices
- Implement network segmentation to isolate IoT devices and limit lateral movement potential
- Regularly audit device configurations for unauthorized changes
How to Mitigate CVE-2025-9149
Immediate Actions Required
- Restrict network access to the Wavlink device's management interface to trusted IP addresses only
- Place the affected device behind a firewall and limit access to administrative interfaces
- Change default credentials and implement strong authentication for device management
- Monitor the device for signs of compromise until a vendor patch is available
Patch Information
At the time of publication, no official patch from Wavlink has been documented in the vulnerability databases. Organizations should monitor the vendor's official channels for firmware updates addressing this vulnerability. The vulnerability affects firmware version M16U1_V240425.
For the latest vulnerability information, consult the VulDB entry and the GitHub security research.
Workarounds
- Disable remote management access to the device's web interface if not required
- Implement network-level access control lists (ACLs) to restrict access to the CGI endpoints
- Deploy a reverse proxy with input validation to filter malicious requests before they reach the device
- Consider replacing the vulnerable device if vendor support is unavailable or patches are not forthcoming
Network segmentation example to isolate vulnerable IoT devices:
# Example iptables rules to restrict access to Wavlink device management interface
# Replace 192.168.1.100 with the IP of your Wavlink device
# Replace 10.0.0.0/24 with your trusted management network
# Block all incoming connections to device web interface
iptables -A FORWARD -d 192.168.1.100 -p tcp --dport 80 -j DROP
iptables -A FORWARD -d 192.168.1.100 -p tcp --dport 443 -j DROP
# Allow only trusted management network
iptables -I FORWARD -s 10.0.0.0/24 -d 192.168.1.100 -p tcp --dport 80 -j ACCEPT
iptables -I FORWARD -s 10.0.0.0/24 -d 192.168.1.100 -p tcp --dport 443 -j ACCEPT
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
