CVE-2025-9149 is a command injection vulnerability found in the Wavlink WL-NU516U1 wireless router, specifically in firmware version M16U1_V240425. The vulnerability resides in the /cgi-bin/wireless.cgi script, within the function sub_4032E4, where the Guest_ssid parameter is improperly sanitized. This allows an attacker to inject arbitrary OS commands remotely by manipulating the Guest_ssid argument. The vulnerability is exploitable without user interaction and does not require authentication, making it accessible to unauthenticated remote attackers over the network. The CVSS 4.0 base score is 5.3 (medium severity), reflecting the network attack vector, low attack complexity, no privileges required, and no user interaction needed. The impact on confidentiality, integrity, and availability is rated low, indicating limited but non-negligible consequences if exploited. Although no public exploits are currently known in the wild, the vulnerability has been publicly disclosed, increasing the risk of future exploitation. The lack of available patches or mitigation from the vendor at this time further exacerbates the risk. Command injection vulnerabilities are critical because they allow attackers to execute arbitrary commands on the device, potentially leading to full device compromise, lateral movement within networks, or use of the device as a foothold for further attacks. Given that this affects a network device, exploitation could disrupt network operations or expose sensitive network configurations and data.

For European organizations, this vulnerability poses a moderate risk primarily to those using the Wavlink WL-NU516U1 router model with the affected firmware. Exploitation could lead to unauthorized command execution on the router, potentially allowing attackers to alter network configurations, intercept or redirect traffic, or pivot into internal networks. This could compromise confidentiality and integrity of data traversing the network and impact availability if the device is destabilized or taken offline. Small and medium enterprises (SMEs) and home office setups, which often rely on consumer-grade routers like Wavlink, are particularly vulnerable. Critical infrastructure organizations and enterprises using these devices in less secure network segments may face increased risk of lateral movement by attackers. The medium severity rating suggests that while the impact is not catastrophic, it is significant enough to warrant prompt attention to prevent escalation or chaining with other vulnerabilities. The absence of authentication requirements and user interaction means attackers can exploit this remotely and autonomously, increasing the threat surface. European organizations with remote or distributed workforces using these devices are at heightened risk due to exposure over public or semi-public networks.

1. Immediate mitigation should include isolating affected Wavlink WL-NU516U1 devices from critical network segments and limiting their exposure to untrusted networks until a patch is available. 2. Network administrators should implement strict firewall rules to restrict access to the router’s management interfaces, especially blocking access to /cgi-bin/wireless.cgi from untrusted sources. 3. Monitor network traffic for unusual or suspicious requests targeting the Guest_ssid parameter or the wireless.cgi endpoint. 4. Employ network intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics to detect command injection attempts against this router model. 5. Encourage users and administrators to upgrade firmware as soon as an official patch is released by Wavlink. 6. As a temporary workaround, if possible, disable the guest wireless network feature or the vulnerable CGI endpoint to eliminate the attack vector. 7. Conduct regular audits of network devices to identify and inventory all Wavlink WL-NU516U1 routers to ensure no devices remain unpatched or exposed. 8. Educate IT staff about this vulnerability to recognize exploitation signs and respond promptly.