CVE-2024-6143 is a classic buffer overflow vulnerability (CWE-120) found in the Actiontec WCB6200Q router's HTTP server component, specifically within the uh_tcp_recv_header function. The vulnerability stems from the failure to properly validate the length of user-supplied data before copying it into a fixed-size buffer, enabling an attacker to overflow the buffer. This overflow can be exploited remotely by an attacker positioned on the same network or adjacent network segment, without requiring any authentication or user interaction. Successful exploitation allows arbitrary code execution within the context of the HTTP server process, potentially leading to full system compromise, including unauthorized access, data manipulation, and denial of service. The affected firmware version is 1.2L.03.5, and the vulnerability was publicly disclosed on June 18, 2024. The CVSS v3 base score is 8.8, reflecting high severity due to the ease of exploitation (low attack complexity, no privileges or user interaction required) and the broad impact on confidentiality, integrity, and availability. Although no active exploits have been reported in the wild, the vulnerability represents a significant risk given the widespread use of Actiontec routers in residential and enterprise environments. The lack of available patches at the time of disclosure necessitates immediate mitigation efforts to reduce exposure.

The impact of CVE-2024-6143 is substantial for organizations using the affected Actiontec WCB6200Q routers. Exploitation can lead to remote code execution, allowing attackers to gain control over the router, intercept or manipulate network traffic, deploy malware, or pivot to internal networks. This compromises confidentiality by exposing sensitive data, integrity by enabling unauthorized changes, and availability by potentially causing device crashes or network outages. Given that authentication is not required, attackers can exploit this vulnerability from adjacent networks, increasing the attack surface. Organizations relying on these routers for critical connectivity, including ISPs, enterprises, and residential users, face risks of service disruption, data breaches, and further network infiltration. The absence of known exploits currently provides a window for proactive defense, but the high severity score underscores the urgency of addressing this vulnerability.

1. Immediate mitigation should focus on network segmentation to restrict access to the router's HTTP management interface, limiting it to trusted administrative hosts only. 2. Disable remote management features if not required, especially HTTP-based management interfaces. 3. Monitor network traffic for unusual or malformed HTTP requests targeting the router to detect potential exploitation attempts. 4. Employ intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics capable of identifying buffer overflow attempts against the HTTP server. 5. Contact Actiontec for firmware updates or security advisories; apply patches promptly once available. 6. If patching is delayed, consider deploying network-level firewall rules to block suspicious traffic patterns or known exploit vectors targeting the router. 7. Regularly audit and update router firmware and configurations to minimize exposure to known vulnerabilities. 8. Educate network administrators about the risks of unauthenticated remote code execution vulnerabilities and enforce strict access controls.