CVE-2024-39789 is a critical security vulnerability identified in the Wavlink AC3000 router firmware version M33A8.V5030.210505. The vulnerability arises from multiple external configuration control weaknesses within the nas.cgi set_ftp_cfg() functionality, specifically targeting the ftp_port POST parameter. An attacker with authenticated HTTP access can craft malicious requests that bypass permission checks, allowing unauthorized modification of system configuration settings. This is classified under CWE-15, which involves external control of system or configuration settings, potentially leading to severe impacts on device behavior. The vulnerability affects confidentiality, integrity, and availability, as attackers can alter FTP configuration parameters, potentially redirecting traffic, disabling security controls, or causing denial of service. The CVSS v3.1 score of 9.1 reflects the ease of network-based exploitation with low attack complexity, requiring high privileges but no user interaction, and the broad scope of impact. Although no public exploits are currently known, the critical nature of this flaw necessitates urgent attention. The vulnerability is particularly dangerous because it allows configuration injection, which can be leveraged for persistent control or lateral movement within networks. The lack of available patches at the time of publication increases the risk for affected users. Organizations relying on Wavlink AC3000 routers should prioritize mitigation to prevent exploitation.

For European organizations, exploitation of CVE-2024-39789 could lead to unauthorized changes in router configurations, compromising network security and stability. This may result in interception or redirection of sensitive data, disruption of FTP services, or broader network outages. Given the router’s role in managing network traffic, attackers could leverage this vulnerability to establish persistent access or pivot to internal systems, threatening confidentiality and integrity of corporate data. Critical infrastructure providers, SMEs, and enterprises using Wavlink AC3000 devices are at heightened risk, especially if these devices are exposed to untrusted networks or insufficiently protected management interfaces. The impact extends to potential regulatory non-compliance under GDPR if personal data confidentiality is breached. Additionally, service disruptions could affect business continuity and damage organizational reputation.

1. Immediately restrict access to the router’s management interface to trusted networks and users only, employing network segmentation and firewall rules. 2. Enforce strong authentication mechanisms and change default credentials to prevent unauthorized authenticated access. 3. Monitor network traffic for unusual HTTP requests targeting nas.cgi or FTP configuration endpoints. 4. Disable FTP services if not required or restrict FTP configuration changes through administrative policies. 5. Regularly audit router configurations for unauthorized changes. 6. Engage with Wavlink or authorized vendors for firmware updates or patches addressing this vulnerability as they become available. 7. Implement network intrusion detection/prevention systems (IDS/IPS) to detect exploitation attempts. 8. Educate IT staff about this vulnerability to ensure rapid response to suspicious activity. 9. Consider deploying alternative hardware or software solutions if patching is delayed.