CVE-2025-57069 is a stack overflow vulnerability identified in the Tenda G3 router firmware version 3.0br_V15.11.0.17. The vulnerability exists in the getsinglepppuser function, specifically in the handling of the pPppUser parameter. A stack overflow occurs when the input to this parameter exceeds the buffer size allocated on the stack, leading to memory corruption. This flaw can be triggered remotely by sending a specially crafted request to the affected device. Exploitation of this vulnerability results in a Denial of Service (DoS) condition, causing the router to crash or become unresponsive. There is no indication that this vulnerability allows for remote code execution or privilege escalation, but the DoS impact can disrupt network connectivity. The vulnerability does not require authentication or user interaction, making it easier for attackers to exploit if the device is exposed to untrusted networks. Currently, there are no known exploits in the wild and no patches have been released. The affected version is specifically the Tenda G3 firmware 3.0br_V15.11.0.17, and no other versions are mentioned. The lack of a CVSS score means severity must be assessed based on the impact and exploitability factors.

For European organizations, the impact of this vulnerability primarily involves network availability and operational continuity. Tenda routers are often used in small to medium-sized enterprises and home office environments. A successful DoS attack could disrupt internet access, internal communications, and critical business operations reliant on network connectivity. This could lead to productivity losses, potential financial impact, and reputational damage if services are interrupted. In sectors such as finance, healthcare, or critical infrastructure, even temporary network outages can have significant consequences. Additionally, if attackers use this vulnerability as part of a broader attack chain, it could facilitate lateral movement or distraction while other attacks are conducted. The lack of authentication requirement increases the risk, especially for devices exposed to the internet or poorly segmented networks. However, the absence of known exploits and patches currently limits immediate widespread impact.

Organizations using Tenda G3 routers should first identify if they are running the vulnerable firmware version 3.0br_V15.11.0.17. Since no official patches are currently available, immediate mitigation steps include restricting access to the router's management interfaces by implementing network segmentation and firewall rules to block untrusted inbound traffic. Disabling remote management features or limiting them to trusted IP addresses can reduce exposure. Monitoring network traffic for unusual or malformed requests targeting the pPppUser parameter could help detect exploitation attempts. Organizations should also plan to update the firmware as soon as a vendor patch is released. In the interim, consider deploying network-level DoS protection mechanisms and ensure robust incident response procedures are in place to quickly recover from potential outages. Regular backups of router configurations and network device inventories will aid in rapid restoration if needed.