CVE-2025-63457 is a stack overflow vulnerability identified in the Tenda AX-1803 router firmware version 1.0.0.1. The flaw resides in the handling of the wanMTU parameter within the sub_4F55C function, where improper input validation leads to a stack overflow condition. An attacker can exploit this by sending a specially crafted request to the router's WAN interface, triggering the overflow and causing the device to crash or reboot, resulting in a Denial of Service (DoS). This vulnerability does not require authentication or user interaction, making it accessible to remote attackers with network access to the WAN interface. The absence of a CVSS score indicates that the vulnerability is newly published and not yet fully assessed, but the technical details suggest a significant impact on device availability. No patches or exploits are currently documented, so organizations must proactively monitor vendor advisories. The vulnerability primarily affects the availability of the router, potentially disrupting internet connectivity and network operations for users relying on this device. The Tenda AX-1803 is commonly deployed in SOHO environments, which may be prevalent in various European countries, increasing the risk of widespread impact if exploited.

The primary impact of CVE-2025-63457 is on the availability of network infrastructure, as exploitation leads to Denial of Service by crashing the router. For European organizations, especially small businesses and home offices using Tenda AX-1803 routers, this could result in loss of internet connectivity, disruption of business operations, and potential downtime. Critical services relying on continuous network access may be interrupted, affecting productivity and potentially causing financial losses. Additionally, repeated exploitation attempts could lead to increased operational costs due to troubleshooting and device replacement. While confidentiality and integrity are not directly impacted, the loss of availability can indirectly affect organizational security posture by forcing fallback to less secure or unmanaged network solutions. The lack of known exploits reduces immediate risk, but the ease of exploitation and remote attack vector necessitate prompt attention.

1. Immediately restrict WAN-side access to the router’s management interfaces by implementing firewall rules or access control lists to limit exposure to untrusted networks. 2. Monitor Tenda’s official channels for firmware updates addressing this vulnerability and apply patches promptly once available. 3. Employ network segmentation to isolate vulnerable devices from critical infrastructure to minimize impact in case of exploitation. 4. Use intrusion detection/prevention systems (IDS/IPS) to monitor for anomalous traffic patterns targeting the wanMTU parameter or unusual requests to the router. 5. Educate users and administrators about the risks of exposing router management interfaces to the internet and enforce strong network perimeter controls. 6. Consider deploying alternative or additional network devices with robust security postures in environments where Tenda AX-1803 routers are critical.