CVE-2024-39788 is a critical external control of system or configuration setting vulnerability (CWE-15) found in the Wavlink AC3000 router firmware version M33A8.V5030.210505. The flaw resides in the nas.cgi script, specifically in the set_ftp_cfg() function, which handles FTP configuration settings. An attacker with valid authentication credentials can send specially crafted HTTP POST requests targeting the ftp_name parameter to inject malicious configuration data. This injection bypasses normal permission checks, allowing unauthorized modification of system settings. The vulnerability affects confidentiality, integrity, and availability by enabling attackers to alter FTP configurations, potentially leading to unauthorized data access, persistent backdoors, or denial of service. The CVSS 3.1 score of 9.1 reflects network attack vector, low attack complexity, required privileges (authenticated), no user interaction, and a scope change with high impact on confidentiality, integrity, and availability. Although no public exploits have been observed, the vulnerability’s nature and severity make it a high-risk target for attackers. The vulnerability highlights the risks of insufficient input validation and improper access control in embedded device management interfaces. Given the critical role of routers in network security, exploitation could facilitate lateral movement, data exfiltration, or network disruption.

For European organizations, exploitation of CVE-2024-39788 could lead to severe consequences including unauthorized access to internal networks, interception or manipulation of sensitive data, and disruption of network services. Organizations relying on Wavlink AC3000 routers, especially in sectors like finance, healthcare, government, and critical infrastructure, face increased risk of espionage, data breaches, and operational downtime. The vulnerability’s ability to bypass permission controls means attackers can escalate privileges and potentially implant persistent threats within the network. Given the router’s role as a gateway device, compromise could enable attackers to pivot to other internal systems, undermining overall network security. Additionally, organizations with remote management enabled or insufficient network segmentation are particularly vulnerable. The lack of known public exploits currently provides a window for proactive mitigation, but the critical severity demands urgent attention to prevent future attacks.

1. Immediately verify if your Wavlink AC3000 devices run the vulnerable firmware version M33A8.V5030.210505 and prioritize their remediation. 2. Apply any available firmware updates from Wavlink addressing this vulnerability; if no patch is available, contact the vendor for guidance or mitigation timelines. 3. Restrict access to the router’s management interface by implementing network segmentation and firewall rules to limit HTTP management access to trusted internal IP addresses only. 4. Enforce strong authentication mechanisms and change default credentials to reduce the risk of credential compromise. 5. Disable FTP services if not required or restrict FTP configuration changes to highly trusted administrators. 6. Monitor network traffic for unusual HTTP POST requests targeting nas.cgi or abnormal FTP configuration changes. 7. Implement intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics to detect exploitation attempts. 8. Conduct regular security audits and penetration testing focusing on router management interfaces. 9. Educate IT staff about the risks of configuration injection vulnerabilities and the importance of timely patching. 10. Consider deploying network access control (NAC) solutions to enforce device compliance and reduce exposure.