CVE-2025-57059 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 dhcpIndex parameter within the addDhcpRule function. A stack overflow occurs when the input data exceeds the buffer capacity allocated on the stack, potentially overwriting adjacent memory and causing unpredictable behavior. In this case, an attacker can craft a malicious request targeting the dhcpIndex parameter to trigger the 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. There is no indication that this vulnerability allows for remote code execution or privilege escalation, and no known exploits are currently reported in the wild. The vulnerability was reserved in August 2025 and published in September 2025, but no CVSS score or patches have been provided yet. The lack of patch links suggests that remediation may not be available at this time. The vulnerability affects a specific firmware version of the Tenda G3 router, a device commonly used in home and small office environments for network routing and DHCP services.

For European organizations, the impact of this vulnerability primarily revolves around network availability and operational continuity. If exploited, the Denial of Service condition could disrupt internet access and internal network communications, affecting business operations, especially for small and medium enterprises relying on Tenda G3 routers. Critical services dependent on continuous network uptime, such as VoIP, cloud applications, and remote work infrastructure, could be interrupted. While the vulnerability does not appear to compromise data confidentiality or integrity directly, the resulting downtime could lead to productivity losses and potential financial impact. Additionally, repeated or targeted exploitation could be used as part of a larger attack strategy to cause disruption or as a diversion for other malicious activities. Given that Tenda routers are often deployed in less hardened environments, the risk of exploitation may be higher in organizations with limited IT security resources.

Organizations should first identify any Tenda G3 routers running the affected firmware version 3.0br_V15.11.0.17 within their network. Since no official patches are currently available, immediate mitigation steps include restricting access to the router's management interface from untrusted networks and implementing network segmentation to isolate vulnerable devices. Monitoring network traffic for unusual DHCP requests or malformed packets targeting the dhcpIndex parameter can help detect attempted exploitation. Employing intrusion detection/prevention systems (IDS/IPS) with custom signatures to flag suspicious DHCP traffic is advisable. Organizations should also consider replacing or upgrading affected routers to models with updated firmware once patches are released. Maintaining regular backups of router configurations and having a recovery plan to quickly restore network functionality after a DoS event is critical. Finally, keeping abreast of vendor advisories and applying firmware updates promptly upon release will mitigate future risks.