CVE-2026-3613 is a stack-based buffer overflow vulnerability identified in the Wavlink WL-NU516U1 wireless network adapter, version V240425. The flaw exists in the sub_401A0C function within the /cgi-bin/login.cgi script, where improper validation of the 'ipaddr' parameter allows an attacker to overflow the stack buffer. This vulnerability can be exploited remotely without requiring user interaction or authentication, making it highly accessible to attackers. The buffer overflow could enable execution of arbitrary code with the privileges of the affected process, potentially leading to full system compromise, including unauthorized access, data manipulation, or denial of service. The CVSS 4.0 score is 8.6, reflecting high severity due to network attack vector, low attack complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. Although no active exploitation has been reported, a public exploit is available, increasing the urgency for mitigation. The vendor has been informed, but no patch links are currently provided. This vulnerability affects a specific firmware version, indicating that updating firmware or applying vendor-provided patches when available is critical. The vulnerability highlights risks in embedded device CGI interfaces, which often lack robust input validation, making them attractive targets for attackers aiming to compromise network infrastructure devices.

The impact of CVE-2026-3613 on organizations worldwide is significant due to the potential for remote code execution on network devices without authentication. Successful exploitation could lead to unauthorized control over the affected Wavlink WL-NU516U1 devices, enabling attackers to intercept or manipulate network traffic, pivot within internal networks, or disrupt network availability. This can compromise confidentiality by exposing sensitive data, integrity by altering device configurations or data, and availability by causing device crashes or denial of service. Organizations relying on these devices for critical network connectivity, especially in enterprise, industrial, or governmental environments, face increased risk of espionage, data breaches, or operational disruption. The availability of a public exploit increases the likelihood of attacks, including automated scanning and exploitation by opportunistic threat actors. The lack of a current patch further exacerbates the risk, necessitating immediate mitigation efforts. The vulnerability could also serve as an entry point for advanced persistent threats targeting strategic infrastructure or high-value targets.

Organizations should immediately inventory their network to identify any Wavlink WL-NU516U1 devices running firmware version V240425. Until an official patch is released, mitigate risk by restricting access to the device management interface, especially the /cgi-bin/login.cgi endpoint, using network segmentation and firewall rules to limit exposure to trusted management networks only. Disable remote management features if not required. Employ intrusion detection or prevention systems to monitor and block suspicious requests targeting the 'ipaddr' parameter or unusual CGI requests. Regularly monitor vendor communications for firmware updates or patches and apply them promptly once available. Consider replacing affected devices with alternative hardware if patching is delayed or unavailable. Additionally, implement network-level protections such as VPNs for remote management and enforce strong authentication and logging to detect potential exploitation attempts. Conduct penetration testing and vulnerability scanning focused on embedded device interfaces to proactively identify similar weaknesses.