CVE-2025-57087 is a high-severity vulnerability identified in the Tenda W30E router firmware version V16.01.0.19 (build 5037). The flaw is a stack-based buffer overflow located in the handling of the 'countryCode' parameter within the 'werlessAdvancedSet' function. This vulnerability arises because the input to the countryCode parameter is not properly validated or bounds-checked, allowing an attacker to send a crafted request that overflows the stack buffer. The consequence of this overflow is a Denial of Service (DoS) condition, where the router may crash or become unresponsive, disrupting network connectivity. The vulnerability is remotely exploitable over the network without requiring authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). Although no known exploits are currently reported in the wild, the ease of exploitation and the critical network role of the affected device make this a significant threat. The vulnerability is classified under CWE-121, which corresponds to classic stack-based buffer overflow issues, often leading to crashes or potential code execution if further exploited. However, in this case, the impact is limited to availability disruption. No patches or mitigation links have been published yet, indicating that affected users and organizations must be vigilant and consider interim protective measures.

For European organizations, the impact of this vulnerability can be substantial, especially for those relying on Tenda W30E routers in their network infrastructure. The DoS condition can lead to network outages, interrupting business operations, communications, and access to critical services. This is particularly concerning for sectors requiring high availability such as finance, healthcare, and public administration. The disruption could also affect remote work capabilities and IoT device connectivity if these routers are used in home or branch office environments. Given the vulnerability requires no authentication and can be triggered remotely, attackers could leverage this flaw to cause widespread network instability or targeted disruption campaigns. Although no data confidentiality or integrity is directly compromised, the loss of availability can indirectly impact operational security and compliance with regulations such as GDPR if services are interrupted.

Since no official patches are currently available, European organizations should implement the following specific mitigations: 1) Immediately identify and inventory all Tenda W30E routers in use, including those in remote or branch locations. 2) Restrict network access to the router management interfaces by implementing strict firewall rules and network segmentation to limit exposure to untrusted networks, especially the internet. 3) Disable or restrict remote management features if not essential, reducing the attack surface. 4) Monitor network traffic for unusual or malformed requests targeting the 'countryCode' parameter or related management endpoints, using intrusion detection/prevention systems (IDS/IPS) with custom signatures if possible. 5) Prepare incident response plans to quickly recover from potential DoS events, including router reboots or replacements. 6) Engage with Tenda support channels to obtain firmware updates or security advisories and plan for timely patch deployment once available. 7) Consider temporary replacement of vulnerable devices in critical environments with alternative hardware until a fix is released.