CVE-2025-57063 is a stack overflow vulnerability identified in the Tenda G3 router firmware version 3.0br_V15.11.0.17. The flaw exists specifically in the handling of the portMappingIndex parameter within the formDelPortMapping function. A stack overflow occurs when the application writes more data to a buffer located on the stack than it can hold, potentially overwriting adjacent memory. In this case, an attacker can craft a malicious request targeting the portMappingIndex parameter to trigger this overflow. The primary consequence of this vulnerability is a Denial of Service (DoS) condition, where the router may crash or become unresponsive, disrupting network connectivity. No evidence currently indicates exploitation in the wild, and no patches or fixes have been published at this time. The vulnerability does not require authentication or user interaction, increasing its risk profile. However, the impact is limited to DoS rather than remote code execution or data compromise. The affected device, Tenda G3, is a consumer-grade router commonly used in home and small office environments. The lack of a CVSS score necessitates an expert severity assessment based on the technical details provided.

For European organizations, the impact of this vulnerability primarily concerns network availability. A successful DoS attack on Tenda G3 routers could disrupt internet access and internal network communications, affecting business operations, especially for small and medium enterprises relying on these devices for connectivity. While the vulnerability does not directly compromise confidentiality or integrity, the resulting downtime could lead to productivity losses and potential secondary impacts such as delayed communications or interrupted services. Critical infrastructure or organizations with remote workforces using vulnerable routers might experience operational challenges. Additionally, the ease of exploitation without authentication raises concerns about potential automated attacks targeting exposed devices. However, the absence of known exploits in the wild and the limited scope to DoS rather than code execution somewhat mitigates the overall risk.

Organizations should first identify if Tenda G3 routers with firmware version 3.0br_V15.11.0.17 are in use within their networks. Given the lack of an official patch, immediate mitigation steps include restricting access to the router's management interface from untrusted networks, especially the internet, by implementing network segmentation and firewall rules. Disabling remote management features or changing default credentials can reduce exposure. Monitoring network traffic for unusual requests targeting the portMappingIndex parameter may help detect exploitation attempts. Organizations should engage with Tenda support or vendors to obtain firmware updates or advisories. As a longer-term measure, consider replacing vulnerable devices with models that receive timely security updates and have a strong security track record. Regularly auditing network devices for known vulnerabilities and maintaining an inventory will improve preparedness against similar threats.