CVE-2024-39764 is a critical security vulnerability identified in the Wavlink AC3000 router firmware version M33A8.V5030.210505. The flaw is an OS command injection (CWE-77) located in the internet.cgi script's set_add_routing() function, specifically via the 'dest' POST parameter. This parameter is improperly sanitized, allowing an authenticated attacker to inject arbitrary operating system commands. Exploitation requires authentication but no user interaction beyond sending a crafted HTTP POST request. Successful exploitation can lead to arbitrary command execution with the privileges of the web server process, which typically runs with elevated rights on the device. The vulnerability impacts confidentiality, integrity, and availability, enabling attackers to manipulate routing tables, disrupt network traffic, install persistent malware, or exfiltrate sensitive data. The CVSS v3.1 score of 9.1 reflects the critical severity, with network attack vector, low attack complexity, high privileges required, no user interaction, and complete compromise of confidentiality, integrity, and availability. No public exploits are currently reported, but the vulnerability's nature and severity 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 affects a specific firmware version, so organizations should verify their device versions to assess exposure.

For European organizations, exploitation of this vulnerability could lead to full compromise of affected Wavlink AC3000 routers, which are often used in small to medium business and home office environments. Attackers could manipulate network routing, intercept or redirect traffic, disrupt internet connectivity, or establish persistent footholds within internal networks. This could facilitate lateral movement, data theft, or ransomware deployment. Critical infrastructure entities relying on these devices for network connectivity may face operational disruptions. The requirement for authentication limits exposure to insiders or attackers who have obtained credentials, but phishing or credential theft could enable remote exploitation. The high severity and potential for complete device compromise make this a significant risk to confidentiality, integrity, and availability of network communications within European organizations.

1. Immediately inventory all Wavlink AC3000 devices and verify firmware versions to identify affected units. 2. Restrict administrative access to the router's web interface by limiting access to trusted IP addresses and enforcing strong authentication mechanisms, including multi-factor authentication if supported. 3. Monitor network traffic and device logs for unusual authenticated HTTP POST requests targeting internet.cgi or abnormal routing table changes. 4. Disable remote management interfaces if not required to reduce attack surface. 5. Apply firmware updates from Wavlink as soon as they become available to patch the vulnerability. 6. If patches are not yet available, consider temporary network segmentation or device replacement for critical environments. 7. Educate users and administrators about the risk of credential compromise and enforce strong password policies. 8. Employ network intrusion detection systems capable of detecting command injection patterns or anomalous router behavior.