CVE-2025-71024 is a stack-based buffer overflow vulnerability identified in the Tenda AX-3 router firmware version 16.03.12.10_CN. The vulnerability resides in the handling of the serviceName2 parameter within the fromAdvSetMacMtuWan function. When this parameter is supplied with a specially crafted input, it causes a stack overflow condition that leads to a denial of service by crashing or rebooting the device. The vulnerability can be exploited remotely over the network without requiring authentication or user interaction, making it accessible to any attacker with network access to the device. The CVSS v3.1 score of 7.5 reflects the high impact on availability (DoS) and the low attack complexity and no privileges required. Although no known public exploits or patches are currently available, the flaw poses a significant risk to network stability for affected users. The vulnerability is classified under CWE-121 (Stack-based Buffer Overflow), a common and well-understood software weakness. This issue primarily affects the availability of the device, potentially disrupting internet connectivity and network services dependent on the router. The lack of patches necessitates proactive mitigation to reduce exposure.

For European organizations, exploitation of this vulnerability could lead to denial of service on Tenda AX-3 routers, causing network outages and interruption of critical business services reliant on internet connectivity. This could affect small to medium enterprises and home office environments where such consumer-grade routers are deployed. Disruption of availability can impact productivity, communication, and access to cloud services. In sectors such as finance, healthcare, and manufacturing, even short network downtime can have operational and compliance repercussions. Additionally, widespread exploitation could degrade ISP service quality if many customer premises equipment (CPE) devices are affected. The vulnerability does not expose sensitive data or allow code execution, limiting impact to availability only. However, the ease of remote exploitation without authentication increases the risk of opportunistic attacks, especially in environments with exposed WAN interfaces or weak network segmentation.

Since no official patches are currently available, European organizations should implement the following specific mitigations: 1) Restrict remote access to the router's management interfaces by disabling WAN-side administration or limiting it via firewall rules and VPN access only. 2) Segment the network to isolate critical systems from consumer-grade routers and untrusted networks. 3) Monitor network traffic for unusual or malformed requests targeting the fromAdvSetMacMtuWan function or the serviceName2 parameter patterns. 4) Replace or upgrade affected Tenda AX-3 devices with models that have patched firmware once available. 5) Engage with Tenda support channels to obtain firmware updates or advisories. 6) Educate users and administrators about the risks of exposing router management interfaces to the internet. 7) Employ intrusion detection/prevention systems (IDS/IPS) to detect and block exploit attempts targeting this vulnerability. These targeted actions go beyond generic advice by focusing on access control, monitoring, and device replacement strategies tailored to this specific vulnerability.