CVE-2025-11300 is a high-severity buffer overflow vulnerability identified in the Belkin F9K1015 router, specifically version 1.00.10. The vulnerability arises from improper handling of the 'ateFunc' argument within an undisclosed function located in the /goform/formWlanMP endpoint. This flaw allows an attacker to remotely send crafted requests to the router's web interface, triggering a buffer overflow condition. The overflow can lead to arbitrary code execution or denial of service, compromising the device's confidentiality, integrity, and availability. The vulnerability requires no user interaction and no authentication, making it remotely exploitable over the network. The vendor, Belkin, was notified early but has not responded or released a patch, increasing the risk of exploitation. Although no known exploits have been observed in the wild yet, a public exploit has been released, which significantly raises the likelihood of active exploitation attempts. The CVSS v4.0 base score of 8.7 reflects the critical nature of this vulnerability, with network attack vector, low attack complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. This vulnerability affects a widely deployed consumer and small office router model, which is often used as a gateway device, making it a valuable target for attackers seeking to compromise home or small business networks.

For European organizations, this vulnerability poses a significant risk, especially for small and medium enterprises (SMEs) and home office environments that rely on Belkin F9K1015 routers for internet connectivity. Successful exploitation could allow attackers to gain unauthorized access to internal networks, intercept or manipulate sensitive data, disrupt network availability, or use compromised routers as pivot points for further attacks. The lack of vendor response and patch availability increases the window of exposure. Given the router's role as a network gateway, exploitation could undermine network perimeter defenses, potentially leading to data breaches or service disruptions. Additionally, the public availability of an exploit increases the risk of automated scanning and mass exploitation campaigns targeting vulnerable devices across Europe. This could impact critical sectors that depend on reliable network infrastructure, including healthcare, finance, and government services, especially in environments where these routers are deployed without additional security controls.

Immediate mitigation steps include isolating the vulnerable Belkin F9K1015 devices from critical network segments and restricting access to the router's management interface to trusted IP addresses only. Network administrators should implement strict firewall rules to block inbound traffic to the /goform/formWlanMP endpoint or the router's web management ports from untrusted networks. Deploying network intrusion detection/prevention systems (IDS/IPS) with signatures tuned to detect exploitation attempts targeting this vulnerability can provide early warning and block attacks. Organizations should conduct asset inventories to identify all affected devices and consider replacing them with routers from vendors that provide timely security updates. Until an official patch is released, disabling remote management features and using VPNs for remote access can reduce exposure. Monitoring network traffic for unusual patterns or spikes in traffic to the router's management interface is also advised. Finally, educating users about the risks and encouraging regular firmware updates for all network devices can help mitigate similar vulnerabilities in the future.