CVE-2024-39800 is a critical security vulnerability identified in the Wavlink AC3000 router firmware version M33A8.V5030.210505. The flaw resides in the openvpn.cgi script, specifically within the openvpn_server_setup() function, which improperly handles external configuration input. The vulnerability is classified under CWE-15, indicating external control of system or configuration settings. An attacker with valid authentication credentials can craft malicious HTTP POST requests targeting the 'open_port' parameter, leading to configuration injection. This injection enables arbitrary command execution on the underlying system, effectively allowing the attacker to execute commands with the privileges of the router's web service. The vulnerability has a CVSS 3.1 base score of 9.1, reflecting its critical nature, with attack vector network (AV:N), low attack complexity (AC:L), requiring privileges (PR:H), no user interaction (UI:N), and scope changed (S:C). The impact includes full compromise of confidentiality, integrity, and availability of the device and potentially the network it serves. Although no exploits are currently known in the wild, the vulnerability’s characteristics make it a high-risk target for attackers. The lack of available patches at the time of publication increases the urgency for mitigation. The vulnerability could be leveraged to disrupt network services, intercept or manipulate data, or pivot into internal networks, posing significant risks to affected organizations.

For European organizations, the impact of CVE-2024-39800 can be severe. Wavlink AC3000 routers are commonly used in small to medium enterprises and some home office environments across Europe. Successful exploitation could lead to full device compromise, allowing attackers to intercept sensitive communications, disrupt network availability, or use the compromised router as a foothold for lateral movement within corporate networks. This could result in data breaches, operational downtime, and loss of trust. Critical infrastructure or organizations with remote VPN access relying on these routers are particularly at risk. The vulnerability’s requirement for authentication limits exposure to some extent but does not eliminate risk, especially if credentials are weak, reused, or obtained via phishing or other means. Given the criticality of network infrastructure in European regulatory environments such as GDPR and NIS Directive, exploitation could also lead to regulatory penalties and reputational damage.

1. Immediately identify and inventory all Wavlink AC3000 devices running the affected firmware version M33A8.V5030.210505 within the organization. 2. Restrict administrative access to the router’s web interface to trusted networks and use strong, unique credentials to prevent unauthorized authentication. 3. Disable the OpenVPN server functionality if not required, reducing the attack surface. 4. Monitor network traffic and router logs for unusual POST requests targeting openvpn.cgi or unexpected configuration changes. 5. Implement network segmentation to isolate critical systems from devices running vulnerable firmware. 6. Regularly check for firmware updates or security advisories from Wavlink and apply patches as soon as they become available. 7. Consider deploying Web Application Firewalls (WAF) or Intrusion Detection/Prevention Systems (IDS/IPS) with signatures to detect and block exploitation attempts. 8. Educate network administrators on the risks of this vulnerability and enforce strict credential management policies. 9. If patching is delayed, consider temporary mitigations such as disabling remote management or VPN server features until a fix is applied.