CVE-2024-39759 is an OS command injection vulnerability identified in the Wavlink AC3000 router firmware version M33A8.V5030.210505. The flaw resides in the login.cgi script, specifically within the set_sys_init() function that processes the restart_hour_value POST parameter. This parameter is improperly sanitized, allowing an attacker to inject arbitrary OS commands. Because the vulnerable endpoint does not require authentication, any remote attacker can exploit this by sending a crafted HTTP request to the device’s web interface. Successful exploitation results in arbitrary code execution with the privileges of the web server process, which on embedded devices like routers often equates to root-level control. This can lead to full device compromise, enabling attackers to alter configurations, intercept or redirect traffic, deploy persistent malware, or launch further attacks within the network. The vulnerability is classified under CWE-77 (Improper Neutralization of Special Elements used in a Command), highlighting the failure to properly sanitize input before command execution. The CVSS v3.1 base score is 10.0, reflecting the vulnerability’s criticality due to network attack vector, no required privileges, no user interaction, and complete impact on confidentiality, integrity, and availability. No patches or public exploits are currently reported, but the severity and ease of exploitation make this a high-risk issue for affected users.

For European organizations, the impact of CVE-2024-39759 can be severe. Compromise of Wavlink AC3000 routers could lead to unauthorized access to internal networks, interception of sensitive data, disruption of internet connectivity, and potential lateral movement to other critical systems. This is particularly concerning for enterprises, government agencies, and critical infrastructure operators relying on these devices for secure network access. The ability to execute arbitrary commands remotely without authentication means attackers can deploy persistent backdoors or use the compromised routers as launchpads for broader attacks such as ransomware or espionage. The disruption of availability could affect business continuity and critical services. Additionally, the breach of confidentiality and integrity could result in data leaks or manipulation, undermining trust and compliance with regulations such as GDPR. Given the widespread use of consumer and SMB networking equipment in European homes and offices, the vulnerability poses a broad risk across multiple sectors.

1. Immediate network-level mitigation: Block access to the router’s web management interface from untrusted networks, especially the internet, using firewall rules or network segmentation. 2. Disable remote management interfaces if not required to reduce exposure. 3. Monitor network traffic for unusual HTTP requests targeting login.cgi or suspicious command injection patterns. 4. Replace or upgrade affected devices to firmware versions that address this vulnerability once available from Wavlink. Since no patches are currently released, contact Wavlink support for timelines or interim fixes. 5. Employ network intrusion detection/prevention systems (IDS/IPS) with signatures to detect attempts to exploit command injection. 6. Conduct regular audits of router configurations and logs to identify signs of compromise. 7. Educate network administrators about this vulnerability and ensure strict access controls on management interfaces. 8. Consider deploying alternative, more secure networking hardware if timely patching is not feasible.