CVE-2025-9298 is a high-severity stack-based buffer overflow vulnerability found in the Tenda M3 router, specifically version 1.0.0.12. The flaw exists in the function formQuickIndex within the /goform/QuickIndex endpoint. An attacker can remotely exploit this vulnerability by manipulating the PPPOEPassword argument, which leads to a stack-based buffer overflow condition. This type of vulnerability allows an attacker to overwrite the stack memory, potentially enabling arbitrary code execution, denial of service, or system compromise. The vulnerability is remotely exploitable without user interaction and requires low attack complexity, as indicated by the CVSS 4.0 vector (AV:N/AC:L/AT:N/UI:N/PR:L). Although privilege is required at a low level (PR:L), no authentication or user interaction is needed to trigger the overflow. The vulnerability impacts confidentiality, integrity, and availability with high scope and impact metrics, meaning a successful exploit could fully compromise the device. While no official patch links are provided yet, the exploit code has been published, increasing the risk of active exploitation. The Tenda M3 is a consumer-grade router commonly used in home and small office environments, and this vulnerability could be leveraged to gain persistent access to the network or pivot to other internal systems.

For European organizations, particularly small businesses and home office users relying on Tenda M3 routers, this vulnerability poses a significant risk. Exploitation could lead to unauthorized network access, interception or manipulation of network traffic, and disruption of internet connectivity. Compromise of these routers could serve as a foothold for attackers to launch further attacks within corporate or residential networks, potentially leading to data breaches or ransomware infections. Given the remote exploitability and lack of user interaction required, attackers could scan and compromise vulnerable devices en masse. This is especially concerning for sectors with sensitive data or critical infrastructure connections, such as healthcare, finance, and government agencies operating in Europe. The lack of an official patch at the time of disclosure increases the window of exposure, emphasizing the urgency of mitigation.

1. Immediate network segmentation: Isolate Tenda M3 routers from critical network segments to limit lateral movement if compromised. 2. Disable or restrict remote management interfaces on the router to prevent external exploitation. 3. Monitor network traffic for unusual activity originating from or targeting the router, including scanning for attempts to exploit /goform/QuickIndex. 4. Apply any vendor-provided firmware updates as soon as they become available; if no patch is released, consider replacing affected devices with models from vendors with timely security support. 5. Employ network intrusion detection/prevention systems (IDS/IPS) with signatures for this specific exploit once available. 6. Educate users about the risks of using outdated router firmware and encourage regular updates. 7. For organizations with many such devices, conduct an inventory and vulnerability assessment to identify and prioritize remediation of affected routers.