CVE-2025-57569 is a buffer overflow vulnerability identified in the Tenda F3 router firmware version V12.01.01.48_multi and later. The vulnerability arises from improper handling of the 'portList' parameter in the '/goform/setNAT' endpoint. This endpoint is likely part of the router's web management interface responsible for configuring Network Address Translation (NAT) settings. A buffer overflow occurs when input data exceeds the allocated buffer size, potentially allowing an attacker to overwrite adjacent memory. Exploiting this vulnerability could enable an attacker to execute arbitrary code on the router with elevated privileges, cause a denial of service by crashing the device, or manipulate router configurations. Since the vulnerability is in a network-exposed management interface, it may be exploitable remotely without authentication, depending on the router's configuration and exposure to the internet. No CVSS score has been assigned yet, and no known exploits are reported in the wild. The lack of patch information suggests that a fix may not yet be available or publicly disclosed. Given the critical role of routers in network infrastructure, exploitation could compromise the confidentiality, integrity, and availability of network traffic passing through the device.

For European organizations, this vulnerability poses a significant risk, especially for small and medium enterprises (SMEs) and home offices that commonly use consumer-grade routers like the Tenda F3. Successful exploitation could lead to unauthorized access to internal networks, interception or manipulation of sensitive data, disruption of internet connectivity, and potential pivoting to other internal systems. This could result in data breaches, operational downtime, and reputational damage. Critical sectors such as finance, healthcare, and government entities using vulnerable devices could face heightened risks. Additionally, compromised routers could be enlisted in botnets for distributed denial-of-service (DDoS) attacks, impacting broader network stability. The absence of known exploits currently provides a window for mitigation, but the potential for rapid weaponization remains if the vulnerability becomes publicly exploited.

Organizations should immediately audit their network infrastructure to identify the presence of Tenda F3 routers running firmware version V12.01.01.48_multi or later. Given the lack of an official patch, interim mitigations include restricting access to the router's management interface by disabling remote management features and limiting access to trusted internal IP addresses only. Network segmentation should be enforced to isolate vulnerable devices from critical systems. Monitoring network traffic for unusual activity or signs of exploitation attempts is advisable. Where possible, replacing vulnerable routers with devices from vendors that provide timely security updates is recommended. Organizations should also subscribe to vendor advisories and CVE databases to apply patches promptly once available. Implementing strong authentication and regularly changing default credentials can reduce the risk of unauthorized exploitation.